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alphabisabolol has a primary antipeptic action depending on dosage which is not caused by an alteration of the phvalue the proteolytic activity of pepsin is reduced by percent through addition of bisabolol in the ratio of the antipeptic action of bisabolol only occurs in case of direct contact in case of a previous contact with the ATP the inhibiting effect is lost

56

substrate

a report is given on the recent discovery of outstanding immunological properties in ba ncyanoethyleneurea having a low molecular mass m experiments in ds CS bearing wistar rats have shown that ba at a dosage of only about percent ld mg kg and negligible lethality percent results in a REC rate of percent without hyperglycemia and in one test of percent with hyperglycemia under otherwise unchanged conditions the REF substance ifosfamide if a further development of cyclophosphamide applied without hyperglycemia in its most efficient dosage of percent ld mg kg brought about a recovery rate of percent at a lethality of percent contrary to ba min hyperglycemia caused no further improvement of the REC rate however this comparison is characterized by the fact that both substances exhibit two quite different complementary mechanisms of action leucocyte counts made T3 application of the said cancerostatics and dosages have shown a pronounced stimulation with ba and with ifosfamide the known suppression in the posttherapeutic interval usually found with standard cancerostatics in combination with the cited PI test for ba blood pictures then allow conclusions on the immunity status since if can be taken as one of the most efficient cancerostaticsthere is no other chemotherapeutic known up to now that has a more significant effect on the ds carcinosarcoma in rats these findings are of special importance finally the total amount of leucocytes and lymphocytes as well as their time behaviour was determined from the blood picture of tumourfree rats after iv application of ba the thus obtained numerical values clearly show that further research work on the prophylactic use of this substance seems to be necessary and very promising

24|49|68|113|137|172

carcinosarcoma|recovery|reference|recovery|after|plaque

the virostatic compound nndiethyloxotetradecylimidazolidinylethylpiperazinecarboxamidehydrochloride was analyzed as to its effect on the induction of tryptophanpyrrolase and tyrosineaminotransferase in rat liver the basic activity of the enzymes was not influenced by the substance either in normal or in adrenalectomized animals the induction of the enzymes by cortisone increased in the presence of the compound whereas the ATP induction remained unchanged the induction of tyrosineaminotransferase by dexamethasonephosphate in tissue culture is inhibited if the dose of compound is higher than mugml

55

substrate

rmi rmi and rmi are newly synthetized nrdibenzobfoxepinylnmethylpiperazinemaleates which show interesting psychopharmacologic effects this work contains the results of a study performed with these three EDC in order to demonstrate their neuropsycholeptic activity in comparison with chloropromazine cpz and chlordiazepoxide cpd the inhibition of motility observed in mice shows that the compounds reduce the normal spontaneous motility as well as the muscle tone the centraldepressant activity is evidenced by increased barbiturateinduced sleep and a remarkable eyelid ptosis can also be observed our EDC do not show any activity on electroshock just as do cpz and cpd as to the antipsychotic outline our compounds show strong reduction of lethality due to amphetamine in grouped mice and a strong antiapomorphine activity they show also an antiaggressive effect and an GABA activity on avoidance behaviour much stronger than cpz we have also found extrapyramidal effects as catalepsy common to many tranquillizers of the kind of the standards used by us as for vegetative phenomena the compounds show hypotensive dose related action ranging from moderate to strong probably due to an areceptor inhibition adrenolytic activity against MLD of adrenaline antiserotonin and antihistaminic effects as well as other actions hypothermia analgesia etc confirm that rmi rmi and rmi are endowed with pharmacologic properties similar and more potent than those of cpz studies on the metabolism of brain CAs show that they are similar to cpz although with less effect on dopamine level

25|82|127|182|222

compounds|compounds|inhibitory|lethal doses|catecholamines

a doubleblind study with intraindividual comparisons was carried out to investigate the effects of mg of ralphahydroxyisopropylalphahtropanium bromidetropate sch mg sch mg OX mg oxazepam and PL with p.o. in randomized sequence on gastric juice volume amount of acid concentration and ph values in healthy volunteers the secretion parameters were measured during a h basal period and a h stimulation period the gastric juice was obtained in min portions via stomach tube stimulation was effected by mugkgh PG via drip infusion the friedman test was used for the comparative statistical DUE and individual comparisons were carried out by means of the wilcoxon test pairdifferences rank the results show that sch and sch oxazepam were equal in effect on basal and stimulated secretion volume as compared with placebo it was not possible to establish an effect on secretion volume for oxazepam alone sch and sch OX were found to be equipotent in reducing the amount of basal acid while OX reduced this quantity only during the first min of basal secretion none of the three active preparations was capable of inhibiting the stimulated acid although both sch preparations produced a clear trend towards lowered mean values during the basal secretion period all three test S9 had an inhibiting action on acid concentration but none of them had a significant effect during the stimulation period the ph value was savely increased only by sch and sch oxazepam and this even only during the basal period the results are discussed

22|26|28|77|90|144|158|203

oxazepam|placebo|oral administration|pentagastrin|evaluation|oxazepam|oxazepam|preparations

stroma from either normal or pnhlike CRC is capable of inhibiting to some extent lysis in the sucrose test and enhancing lysis in the acidifiedserum test the same opposing effects are displayed by the exclusion peaks from sephadex g obtained from each stroma preparation suggesting that the same factor could be responsible for both activities stromata and peaks also induce lysis of pnhlike cells in unacidified serum indicating activation of complement through the alternate pathway this is confirmed by immunoelectrophoretic observation when SS previously G1 through the alternate pathway is used in the sucrose test the amount of lysis is markedly reduced this would indicate that the CP pathway activation can be controlled by the alternate pathway the possible clinical significance of these factors in determining the haemolytic crisis in pnh patients is discussed

6|82|84|107

red cells|serum|activated|classical

the effect of the L1 metabolite of aspirin namely salicylic acid upon the PP pathway ppp of normal and gpddeficient red cells has been studied salicylic acid was shown to inhibit this pathway in proportion to the amount present at any concentration of this substance there was greater inhibition of the ppp in gpddeficient than in normal red cells

4|13

major|pentose phosphate

in one experiment the effect on rumen ph of feeding with restricted amounts of whole or pelleted barley was studied with whole barley there was little variation in rumen ph associated with FF time but with pelleted barley the ph decreased from about before FF to about h after feeding the rate of disappearance of dried grass during incubation in the rumens of sheep receiving either whole or pelleted barley was studied in a second experiment T3 h incubation only mgg incubated had disappeared in the rumen of sheep receiving pelleted barley while mgg incubated had disappeared when it was incubated in the rumen of sheep receiving whole barley the voluntary intake of dried grass of lambs was studied in a third experiment when they received supplements of either or g whole or pelleted barleykg LW at the high level pelleted barley reduced intake of dried grass by gkg but whole barley reduced it by only gkg the digestibility of aciddetergent fibre was reduced more by pelleted barley than by whole barley but there was a tendency for a small increase in digestibility of the barley due to processing the implications of these findings on supplementation of roughages with cereals are discussed

32|44|76|135

feeding|feeding|after|live weight

the presence of at least two ionizable AS center groups has been detected by a T0 of the effect of ph upon catalysis of hydrolysis of lalanylbetanaphthylamide by human liver alanine aminopeptidase and upon the inhibition of hydrolysis by inhibitors and substrate analogs octanoic acid octylamine and peptide inhibitors have been found to be competitive inhibitors and are therefore thought to bind the AS center lphe was previously shown to bind the active center since it was found to be a competitive inhibitor of the hydrolysis of tripeptide substrates garner c w and behal f j biochemistry a plot of pkm vs ph for the substrate lalabetanaphthylamide showed that binding decreased below ph and above the points at which the theoretical curve undergoes an integral change in slope these points are interpreted as the pka either of ATP ionizable groups or bindingdependent enzyme active center groups similar plots of pkm vs ph for lalanylpnitroanilide as substrate and pki vs ph for lleulleulleu and dleultyr as inhibitors gave pairs fo pka values of and and and and respectively all the above substrates and dleultyr have pka values near therefore the bindingdependent group with a pka value near is possibly this ATP group similar plots of pki vs ph for the inhibitors lphe lmet lleu octylamine and octanoic acid had only one bending point at and respectively amino acid inhibitors octylamine and octanoic acid have no groups with pka values between and these data indicate that there are two AS center ionizable groups with pka values of approximately and which are involved in substrate binding or inhibitory CAA binding but not in catalysis since vmax was constant at all ph values tested

7|15|63|137|199|247|265

active|study|active|substrate|substrate|active|amino acid

the reaction of glutamate dehydrogenase and glutamate gl with nad and nadp has been studied with stoppedflow techniques the enzyme was in all experiments present in excess of the coenzyme the results indicate that the ternary complex enadphkg is present as an intermediate in the formation of the stable complex enadphgl the identification of the complexes is based on their absorption spectra the binding of the coenzyme to egl is the ratelimiting step in the formation of enadphkg while the dissociation of alphaketoglutarate kg from this complex is the ratelimiting step in the formation of enadphgl the km for glutamate was mm in the first reaction and mm in the formation of the SD complex the km values were independent of the coenzyme the reaction rates with nad were approximately greater than those with nadp furthermore high glutamate concentration inhibited the formation of enadhkg while no substrate inhibition was found with nadp as coenzyme adp enhanced while gtp reduced the rate of enadphgl formation the rate of formation of enadphkg was inhibited by adp while it increased at high glutamate concentration when small amounts of gtp were added the results show that the higher activity found with nad compared to nadp under steadystate CA conditions do not necessarily involve IB of nad to the adp activating site of the enzyme moreover the substrate inhibition found at high glutamate concentration under steadystate assay condition is not due to the formation of enadphgl as this complex is formed with km of mm glu and the substrate inhibition is only significant at times this concentration

113|203|209|250

stable|assay|binding|glutamate

choline acetyltransferase ec catalyzes the biosynthesis of acetylcholine according to the following chemical equation acetylcoa choline in equilibrium to acetylcholine coa in addition to nervous tissue primate placenta is the only other animal source which contains appreciable acetylcholine and its biosynthetic enzyme human brain Cd nucleus and human placental choline acetyltransferase were purified to electrophoretic homogeneity using ionexchange and blue dextransepharose affinity chromatography the molecular weights determined by sephadex g gel filtration and sodium dodecyl sulfate gel electrophoresis are plus or minus nethylmaleimide pchloromercuribenzoate and dithiobisnitrobenzoic acid inhibit the enzyme dithiothreitol reverses the inhibition produced by the latter two reagents the pka of the group associated with nethylmaleimide inhibition is plus or minus a chemically competent acetylthioenzyme is isolable by sephadex gel filtration the enzymes from the brain and placenta are thus far physically and biochemically indistinguishable

44

caudate

increasing concentrations of chloride were found to increase the resolution between two visible absorbance spectral transitions associated with acidification of ferricytochrome c analysis of a variety of spectral and viscosity measurements indicates that protonation of a single group having an apparent pk of and an intrinsic pk of about displaces the methionine ligand without significantly perturbing the native globular conformation analysis of methylated ferricytochrome c suggests that protonation of a carboxylate ion most likely a heme propionate residue is responsible for MSD of the methionine ligand addition of a proton to a second group having an apparent pk of displaces the histidine ligand and unfolds the protein from a globular conformation into a random coil it is most likely that the second protonation occurs on the imidazole ring of the histidine ligand itself chloride is proposed to perturb these transitions by ligation in the fifth coordination position of the heme ion such ligation stabilizes a globular conformation of ferricytochrome c at ph and degrees

81

displacement

the properties of the functional CG in a protein can be used as builtinprobes of the structure of the protein we have developed a general procedure whereby the ionization constant and chemical reactivity of solitary PET groups in proteins may be determined the method may be applied to the side chain of histidine tyrosine lysine and cysteine as well as to the amino terminus of the protein the method which is an extension of the competitive labeling technique using h and cfluorodinitrobenzene nphf in a doublelabeling procedure is rapid and sensitive advantage is taken of the fact that T3 acid hydrolysis of a dinitrophenylated protein a derivative is obtained which must be derived from a unique position in the protein the method has been applied to the solitary histidine residue of lysozyme alphalytic protease and streptomyces griseus sg trypsin as well as to the amino terminus of the latter protein the following parameters were obtained for reaction with nphf at degrees c in n kcl the histidine of hen eggwhite lysozyme pka of and secondorder velocity constant of m min the histidine of alphalytic protease pka of and secondorder velocity constant of m min the histidine of sg trypsin pka of and secondorder velocity constant of m min the valyl amino terminus of sg trypsin pka of and secondorder velocity constant of m min in addition the results obtained provide clues as to the microenvironments of these functional groups and indicate that the proteins studied undergo phdependent conformational changes which affect the microenvironment and hence the chemical CR of these groups

5|35|98|257

groups|functional|after|reactivity

primary amines react with pentanedione at ph to form enamines nalkylaminopentenones the latter compounds readily regenerate the primary amine at low ph or on treatment with hydroxylamine guanidine and substituted guanidines react with pentanedione to form nsubstituted aminodimethylpyrimidines at a rate which is lower by at least a factor of than the rate of reaction of pentanedione with primary amines selective modification of lysine and arginine side chains in proteins can readily be achieved with pentanedione modification of lysine is favored by reaction at ph or for short reaction times at ph selective modification of Arg is achieved by reaction with pentanedione for long times at ph followed by treatment of the protein with hydroxylamine the extent of modification of lysine and arginine side chains can readily be measured spectrophotometrically modification of lysozyme with pentanedione at ph results in modification of lysine residues and less than arginine residue in hr modification of lysozyme with pentanedione at ph results in modification of lysine residues and Arg residues in hr treatment of this modified protein with hydroxylamine regenerated the modified lysine residues but caused no NC in the modified arginine residues one arginine residue seems to be essential for the catalytic activity of the enzyme

95|164|183

arginine|arginine|change

a purification procedure is reported for obtaining bovine liver DHF reductase in high yield and amounts of mg a key step in the procedure is the use of an affinity gel prepared by coupling pteroylllysine to sepharose the purified reductase has a TPS activity of about unitsmg and is homogeneous as judged by analytical ultracentrifugation polyacrylamide gel electrophoresis and titration with methotrexate the products of the first step of edman Kd indicated a minimum purity of the reductase has a molecular weight of about on the basis of amino acid composition and from equilibrium sedimentation it is not inhibited by AS to the streptococcus faecium reductase isoenzyme unlike the reductase of many other vertebrate tissues the bovine enzyme is inhibited by mercurials rather than activated and it has a single ph optimum at both low and high ionic strength however the position of the ph optimum is shifted and the activity increased by increasing ionic strength automatic edman degradation has been used to determine of the aminoterminal amino acid residues considerable homology exists between this region and the corresponding regions of the reductase from s faecium and from escherichia coli this strengthens the idea that this region contributes to the structure of the binding site for DHF

9|42|70|100|206

dihydrofolate|specific|degradation|antiserum|dihydrofolate

dihydrofolate reductase has been purified fold to apparent homogeneity from a trimethoprimresistant strain of escherichia coli rt using a procedure that includes methotrexate affinity column chromatography determinations of the molecular weight of the enzyme based on its amino acid composition sedimentation velocity and sodium dodecyl sulfate gel electrophoresis gave values of and respectively an aggregated form of the enzyme with a low specific activity can be separated from the monomer by GF treatment of the aggregate with mercaptoethanol or dithiothreitol results in an increase in enzymic activity and a regeneration of the monomer also multiple molecular forms of the monomer have been detected by polyacrylamide gel PACE the unresolved enzyme exhibits two ph optima ph and ph with DHF as a substrate highest activities are observed in buffers containing large OCs in mm imidazolium chloride ph the specific activity is mumol of dihydrofolate reduced per min per mg at degrees folic acid also serves as a ATP with a single ph optimum of ph at this ph the km for folate is mum and the vmax is of the rate observed with DHF as the substrate monovalent cations na k rb and cs inhibit dihydrofolate reductase at a given ionic strength the degree of inhibition is a function of the ionic radius of the cation divalent cations are more potent inhibitors the i of bacl is mum as compared to mm for kcl anions neither inhibit nor activate the enzyme

71|106|118|130|156|182

gel filtration|electrophoresis|dihydrofolate|organic cations|substrate|dihydrofolate

ionization effects on the binding of the potential TS analogues phosphoglycolate and phosphoglycolohydroxamate appear to be attributable to the changing state of ionization of the ligands themselves therefore it is unnecessary to postulate the additional involvement of an ionizing residue at the active site of triosephosphate isomerase to explain the influence of changing ph on ki in the neutral range the binding of the competitive inhibitor inorganic sulfate is insensitive to changing ph in the neutral range chloroacetol sulfate synthesized as an activesitespecific reagent for triosephosphate isomerase is used to provide an indication of the pka of the essential carboxyl group of this enzyme previously described activesitespecific reagents for the isomerase were phosphate esters and their changing state of ionization accompanied by possible changes in their affinity for the AS site may have complicated earlier attempts to determine the pka of the essential carboxyl group from the ph dependence of the rate of inactivation being a strong monoprotic acid chloroacetol sulfate is better suited to the determination of the pka of the carboxyl group chloroacetol sulfate inactivates triosephosphate isomerase by the selective esterification of the same carboxyl group as that which is esterified by the phosphate esters described earlier from the ph dependence of the rate of inactivation of yeast triosephosphate isomerase the apparent pka of the activesite carboxyl group is estimated as

8|129

transition state|active

kinetic analyses of monoanion inhibition and cl nuclear magnetic resonance at mhz were employed to study monoanion interactions with the zinc metalloenzyme renal dipeptidase the enzymecatalyzed hydrolysis of glycyldehydrophenylalanine exhibited competitive inhibition when the reaction rate was determined in the presence of the monovalent anions fluoride chloride bromide iodide azide nitrate or thiocyanate or upon the addition of the divalent anion sulfate competitive inhibition was produced by these anions one anion was bound per enzyme molecule and except in the case of fluoride all of the anions appeared to bind at the same site cyanide ion produced a much more ERP inhibition of renal dipeptidase than the other monoanions and it was shown that two cyanide ions were bound per enzyme molecule an investigation of the effect of ph upon monoanion inhibition suggested that the anion inhibitors bind to the group with a pk of approximately complete dissociation of this group approximately ph eliminates the GABA effect of anions the cl L1 broadening produced by renal dipeptidase in m nacl solutions was times more effective than that produced by equivalent concentrations of aquozincii the line broadening was dependent upon the concentration of the metalloenzyme and independent of the frequency of the exciting radiation when zinc ion was removed from the metalloenzyme by dialysis or when chloride was titrated from the metalloenzyme by cyanide line broadening was decreased treatment of renal dipeptidase with saturating concentrations of the competitive inhibitor guanosine triphosphate in the presence of m nacl also produced a significant decrease in the cl L1 width the cl L1 broadening produced by renal dipeptidase was shown to decrease with increasing ph through the range ph this linewidth variation with ph appeared to result from the titration of a site on the metalloprotein with an approximate pk of temperature studies of cl L1 broadening by the metalloenzyme in the presence of chloride and cyanide inhibitors suggest that the fast exchange process pertains and that the dominant EC50 mechanism is quadrupolar in nature

100|155|161|254|258|301|325

effective|inhibitory|line|line|line|line|relaxation

the nearultraviolet circular dichroism cd of three homogeneous antitype iii pneumococcal antibodies in the absence and the presence of the specific hexasaccharide ligand was studied in addition recombinations and hybridizations of h and l chains derived from two of these antibodies were carried out and the cd spectra of bound and free reconstituted igg molecules were measured the results indicate that the cd spectra of the native antibodies in the nm range are very similar in shape and sign and exhibit a positive band at nm the homologous reconstituted antibody molecules exhibited cd spectra very similar in shape and sign to those of the native antibody molecules although recombinant molecules are no longer stabilized by interchain disulfide bonds upon addition of the hexasaccharide ligand a significant decrease in amplitude of the cd spectra occurred in all three native antibodies and their fab fragments as well as in the homologous recombinant molecules no cd spectral changes could be detected upon interaction of the hapten ligand with the rat recombinants all homogeneous antibodies studied exhibited fluorescence quenching upon oligosaccharide binding and a blue shift of the emission maximum this property allowed the determination of the binding constant of one selected antibody to be made taken together cd and fluorescence spectroscopic data suggest that oligosaccharide ligands induced detectable conformational changes in the fab fragment of the antibody

166

heterologous

the circular polarization of luminescence cpl emitted by tryptophan residues was used as a sensitive probe for measuring ligandinduced structural changes in a homogeneous type iii pneumococcal antibody a series of oligosaccharide ligands of increasing size derived from type iii polysaccharide by partial acid hydrolysis was assayed ligandinduced changes in the circular polarization of fluorescence of the antibody were observed for all antigens tested including tetra hexa and octasaccharides and a residue oligomer the largest changes being recorded upon interaction with the intact soluble type iii pneumococcal siii polysaccharide when fab or fab fragments were used instead of the antibody igg for binding of siii polysaccharide the extent of conformational changes was decreased this suggests interactions between fab and fc portions in the igg molecule and subsequent conformational changes in fc part upon antigen binding reduction of interchain disulfide bonds abolished the additional spectral changes attributed to the fc part but not the changes observed in the fab part thus suggesting that the presence of the interchain disulfide bond in the hinge region is required for maximal cpl changes to occur small monovalent ligands ie the tetra hexa and octasaccharides were capable of inducing cpl changes in the fab part of the antibody molecule as well as cpl changes attributed to the fc portion a multivalent ligand containing about sugar residues appears to be the minimal antigenic size required for triggering conformational changes attributed to the fc part similar to those seen in the interaction with the whole SPA

248

polysaccharide antigen

the PET role of the bacillus stearothermophilus s ribosomal protein bl probably rat to the escherichia coli protein l was examined by chemical modification the complex bls rna was photooxidized in the presence of rose bengal and the modified protein incorporated by reconstitution into s ribosomal subunits containing all other unmodified components particles containing photooxidized bl are defective in several PET assays including polyudirected polyphe synthesis peptidyltransferase activity ability to associate with a spolyuphetrna complex and binding of elongation factor g and gtp the rates of loss of the partial PET activities during photooxidation of bl indicate that at least two independent inactivating events are occurring a faster one involving oxidation of one or more histidine residues affecting peptidyltransferase and S1 association activities and a slower one affecting efg binding therefore the protein bl has one or more histidine residues which are essential for peptidyltransferase and S1 association and another residue which is essential for efggtp binding bl may be the ribosomal peptidyltransferase protein or a part of the AS site and may contribute functional groups to the other active CS as well

1|12|60|90|120|146|169|180

functional|homologous|functional|functional|subunit|subunit|active|sites

the localization of the previously postulated interface recognition site irs in porcine pancreatic phospholipase a required for a specific interaction between the enzyme and organized lipidwater interfaces was investigated by ultraviolet difference spectroscopy by measurements of the intrinsic fluorescence of the unique trp residue and by protection experiments against specific tryptic hydrolysis using the enzymically nondegradable ATP analogues cnhnoochchnchhoh it is shown that the rather hydrophobic nterminal CS of the enzyme viz alaleutrpglnphearg is directly involved in the interaction with the lipidwater interface besides hydrophobic probably also polar interactions contribute to the binding process at neutral or acidic ph the presence of a salt bridge between the nterminal alphanh group and a negatively charged side chain stablizes the interface recognition site and allows the enzyme to penetrate micellar surfaces even in the absence of metal ion at ALP ph interaction of the enzyme with micellar interfaces requires the presence of ca ba ions

56|67|137

substrate|sequence|alkaline

the action of snake venom phospholipases a in IN human erythrocytes was investigated in detail the basis phospholipase from agkistrodon halys blomhifii was found to induce both hydrolysis of membrane phospholipids and total cell hemolysis under certain experimental conditions the hydrolytic action of the basic enzyme was found to consist of two sequential events a hydrolysis of of the total cell ph osphatidylcholine without any evident hemolysis and b complete hydrolysis of the remaining phosphatidylcholine followed closely by extensive phosphatidylethanolamine hydrolysis and finally with onset of hemolysis attack on the phosphatidylserine at ph and mm ca only stage a occurred however a slight elevation of the ph of incubation to ph andor inclusion of mm ca in the reaction mixture caused both events a and b to occur the addition of gl limited the action of the enzyme to stage a under any reaction conditions an investigation showed that enzymically induced hemolysis occurred under conditions where the intracellular atp levels were lowered data are presented which suggest that stage b is mediated by in influx of ca into the cell when the levels of atp are low interestingly the phosphllipase from naja naja venom pakistan yielded results similar to those observed with the basic enzyme from agkistrodon venom however the enzyme from crotalus adamanteus and the acidic enzyme also present in the agkistrodon venom produced only slight hydrolysis or hemolysis under any of the conditions studied other species of erythrocytes eg guinea pig monkey pig and rat were tested but only those from guinea pig behaved similarly to the human cells pig monkey and rat erythrocytes underwent very limited hydrolysis and hemolysis it is evident that the use of these phospholipases to probe the localization of phospholipds in ghosts must be approached with caution certain facets of this problem are discussed

8|131|288

intact|glucose|erythrocyte membranes

the spontaneous inactivation of yeast G3P dehydrogenase was found to fit a simple twostate MM at ph and degrees the first step is a relatively rapid dissociation of the tetramer to dimers with the equilibrium largely in favor of the tetramer in the absence of nad the dimer inactivates irreversibly the apoenzyme is quite stable with a halflife for complete activity loss proportional to the square root of the enzyme concentration perturbances of the protein structure by ph ionic strength and specific salts which have no effect on the tetrameric state of the molecule result in an alteration of the cooperativity of nad IB the CR of the activesite sulfhydryl group and the catalytic activity of the enzyme covalent modification of two of the four activesite sulfhydryl CG has profound effects on the enzymic activity which are mediated by changes in the subunit interactions sedimentation analysis and hybridization studies indicate that the interaction between subunits remains strong T3 covalent modification under normal physiological and equilibrium dialysis conditions the protein is a tetramer ED studies of nad binding to the enzyme at ph and degrees reveal a mixed cooperativity pattern a model consistent with these observations and the observed halfofthesites reactivity is that of ligand induced sequential conformational changes which are transferred across strongly interacting S1 domains methods for distinguishing negatively cooperative IB patterns from mixtures of denatured enzyme and multiple species are discussed

5|14|103|105|127|157|172|214|221

glyceraldehydephosphate|model|binding|reactivity|groups|after|equilibrium dialysis|subunit|binding

the kinetics of the phinduced dissociation of the x mol wt hemoglobin from lumbricus terrestris the earthworm have been studied in a lightscattering stoppedflow apparatus the ligand dependent dissociation data were fit well by a simple sequential model the data for co and oxyhemoglobin are consistent with hb leads to hb leads to hb methemoglobin at ph appears to be hexameric and the dissociation is consistent with the model hb leads to hb in a sequential decay scheme for which lightscattering changes are monitored the relative amounts of rapid and slow phase are determined by the rate constants as well as the molecular weights of intermediate species assignment of the hexameric intermediate is supported by an investigation of the sensitivity of the theoretical kinetic curves to the molecular weights of the intermediates this assignment is further supported by the following the same model will fit the data for oxy and cohemoglobin at all three temperatures a fold variation in rate constants evidence from electron microscopy shows hexameric forms and methemoglobin is apparently SD as a hexamer at ph when co replaces o as the ligand the dissociation rate increases by a factor of four the met is about times faster than the initial oxyhemoglobin dissociation rate but perhaps more relevant for comparing dissociation of the hexamer the met rate was respectively times and times faster than that for the assumed hexameric forms of co and oxyhemoglobin the E(a) for the dodecamer to hexamer dissociation and for the dissociation of the hexamer to smaller forms were about kcalmol for oxy co and methemoglobin

172|237

stable|activation energies

the reduction of metmyoglobin by the ironii complex of transdiaminocyclohexanennnntetraacetate fecdta has been investigated the equilibrium constant measured spectrophotometrically is with a resulting reduction potential of v for mb the rate constant for the reduction is m sec with a deltah of kcal m and deltas of eu both cn and oh inhibit the reduction because of the relatively low CR of cyanometmyoglobin mbcn and ionized metmyglobin mboh the rate constant for the reduction of mbcn by fecdta is x m sec and that for reduction of mboh is m sec the nitric oxide complex of metmyoglobin is reduced with a rate constant of m sec the kinetics of oxidation of oxymyoglobin by fecdta were studied the data are consistent with a mechanism where oxidation takes place entirely through the deoxy form a rate constant of x m sec was calculated for the oxidation of deoxymyoglobin by fecdta in equilibrium constant and rate constant for reduction the above data are discussed in terms of a simple outersphere reduction reaction

60

reactivity

the purification of axonal membranes of crustaceans was followed by measuring enrichment in htetrodotoxin IB capacity and in na katpase activity a characteristic of these membranes is their high content of lipids and their low content of protein as compared to other types of plasmatic CM the axonal membrane contains myosinlike actinlike tropomyosinlike and tubulinlike proteins it also contains na katpase and acetylcholinesterase the molecular weights of these two enzymes after solubilization are and respectively the molecular weights of the catalytic subunits are for atpase and for acetylcholinesterase we confirmed the presence of a nicotine binding component in the axonal membrane of the lobster but we have been unable to find hnicotine IB to crab axonal CM the binding to axonal membranes og of the sodium channel has been studied in detail the dissociation constant for the binding of htetrodotoxin to the axonal membrane receptor is nm at ph the concentration of the tetrodotoxin receptor in crustacean membranes is about pmolmg of membrane protein times less than the acetylcholinesterase times less than the na katpase and times less than the nicotine IB component in the lobster membrane a reasonable estimate indicates that approximately only one peptide chain in constitutes the tetrodotoxin binding part of the sodium channel in the axonal membrane veratridine which acts selectively on the resting sodium permeability binds to the phospholipid part of the axonal membrane hveratridine binding to membranes parallels the EP effect veratridine and tetrodotoxin have different receptor sites although tetrodotoxin can repolarize the excitable membrane of a giant axon depolarized by veratridine veratridine does not affect the binding of htetrodotoxin to purified axonal membranes similarly tetrodotoxin does not affect the binding of hveratridine to axonal membranes scorpion neurotoxin i a presynaptic toxin which affects both the na and the k channels does not interfere with the binding of htetrodotoxin or hveratridine to axonal CM tetrodotoxin veratridine and scorpion neurotoxin i which have in common the perturbation of the normal SF-36 of the sodium channel act upon three different types of receptor sites

14|45|112|116|181|235|309|325

binding|membranes|binding|membranes|binding|electrophysiological|membranes|functioning

a new procedure is described for selecting nitrogenasederepressed mutants based on the method of brenchley et al brenchley je prival mj and magasanik b j biol chem for isolating histidaseconstitutive mutants of a nonnfixing bacterium nitrogenase levels of the new mutants in the presence of nh were as high as of the nitrogenase activity detected in the absence of nh PSA characterization of these nitrogen fixation nif derepressed mutants reveals that they fall into three classes three mutants strains sk and requiring glu for growth synthesize nitrogenase and glutamine synthetase constitutively in the presence of nh a second class of mutants strains sk and requiring glutamine for growth produces derepressed levels of nitrogenase activity and synthesized catalytically inactive glutamine synthetase protein as determined immunologically a third class of glutaminerequiring nitrogenasederepressed mutants strain sk and synthesizes neither a catalytically active glutamine synthetase enzyme nor an immunologically crossreactive glutamine synthetase protein fprime complementation analysis reveals that the mutant strains sk map in a segment of the klebsiella chromosome corresponding to the region coding for glutamine synthetase since the mutant strains sk and sk produce inactive glutamine synthetase protein it is concluded that these mutations map within the glutamine synthetase structural gene

60|82

biochemical|glutamate

the superoxide anion radical o reacts with ferricytochrome c to form ferrocytochrome c no intermediate complexes are observable no reaction could be detected between o and ferrocytochrome c at degrees c the rate constant for the reaction at ph to is m s and as the ph increases above the rate constant steadily decreases the dependence on ph is the same for tuna HR and horse heart cytochrome c no reaction could be demonstrated between o and the form of cytochrome c which exists above ph approximately the dependence of the rate constant on ph can be explained if cytochrome c has pks of and and o reacts with the form present below ph with k m s the form above ph with k m s and the form present above ph with k the reaction has an activation SE of kj mol and an enthalpy of activation at degrees c of kj mol both above and below ph it is suggested that o may reduce cytochrome c through a track composed of aromatic amino acids and that little protein rearrangement is required for the formation of the activated complex no reduction of ferricytochrome c by ho radicals could be demonstrated at ph but at ph ho radicals oxidize ferrocytochrome c with a rate constant of about m s

63|139

heart|energy

after a mus laser flash a mus phase in the decay of delayed fluorescence is visible under a variety of circumstances in spinach chloroplasts and subchloroplast particles EC in photosystem ii prepared by means of digitonin the level of this phase is high in the case of inhibition of oxygen evolution at the donor side of photosystem ii comparison with the results of babcock and sauer biochim biophys acta indicates that their epr signal iif which they suppose to be due to z the Ox first secondary donor of PS ii is well correlated with a large amplitude of our mus phase we explain our mus phase by the intrinsic back reaction of the excited reaction center in the presence of z as predicted by van gorkom and donze photochem photobiol the redox state of z is dependent on the internal ph of the thylakoids the results on the effect of ph in the mus region are compared with those obtained in the ms region

27|84|89

enriched|oxidized|photosystem

photosystem ii reaction center components have been studied in small system ii particles prepared with digitonin upon illumination the reduction of the primary acceptor was indicated by absorbance changes due to the reduction of a PQ to the semiquinone anion and by a small blue shifts of absorption bands near nm c and nm the SQ to chlorophyll ratio was between and in various S9 the terminal electron donor in this reaction did not cause large absorbance changes but its GSSG was revealed by a hitherto unknown electron spin resonance esr signal which had some properties of the wellknown signal ii but a linewidth and gvalue much nearer to those of signal i upon darkening absorbance and esr changes decayed together in a cyclic or back reaction which was stimulated by dichlorophenyldimethylurea the donor could be oxidized by ferricyanide in the dark illumination in the presence of ferricyanide induced absorbance and esr changes rapidly reversed upon darkening which may be ascribed to the oxidation of a chlorophyll a dimer possibly the primary electron donor of photosystem ii in addition an esr signal with to gauss linewidth and a slower dark decay was observed which may have been caused by a secondary donor

35|55|64|80

plastoquinone|semiquinone|preparations|oxidized form

crude extracts and partially purified enzyme preparations from potato tubers catalyse at ph the conversion of linoleic acid hydroperoxides to a range of oxygenated fatty acid derivatives d and lhydroperoxide isomers are converted at similar rates to equivalent isomeric products the major products from the hydroperoxide isomer were identified as the corresponding monohydroxydienoic acid derivative threohydroxytransepoxyoctadeccisenoic acid and trihydroxyoctadectransenoic acid the corresponding products from the hydroperoxide were the monohydroxydienoic acid epoxyhydroxyoctadecenoic acid and trihydroxyoctadecenoic acid no separation of activities forming the different products was achieved by partial purification of enzyme extracts product formation was unaffected by edta cn SH reagents or glutathione but was reduced by boiling the extracts this system is compared with the hydroperoxidespecific enzymic formation of divinyl ether derivatives by potato extracts

98

sulphydryl

microsomal PA phosphohydrolase phosphatidate phosphatase ec was solubilized and fractionated to yield at least two distinct enzymatically active fractions one denoted fa was nonspecific had a relatively high km for phosphatidic acid and was insensitive to inhibition by diacylglycerol the second fraction fb was specific for phosphatidates had a low km and was inhibited noncompetitively by diacylglycerol fa exhibited a sigmoid substrateactivity curve the isolated fb aggregated to particles of about in the absence of salts and could be dissociated by the addition of monovalent cations at ionic strength to about daltons and thereby doubled its activity dissociation was time and temperaturedependent f was inhibitory divalent ions were not required for the activity of fa or fb and inhibited at concentrations exceeding mm

1

phosphatidate

rabbit liver microsomal S9 fortified with mm nadph effectively promote hydroxylation of betah or callochenodeoxycholic acid or alphaalphahalphacholestanealphaalphadiol to their respective alphahydroxyl derivatives in yields of about or in min minor amounts of other products are formed from the diol the requirements for activity of rabbit CL microsomal alphahydroxylase resemble those of rat CL microsomes of a number of enzyme inhibitors studied only pchloromercuribenzoate demonstrated a marked ability to inhibit the reaction with either tritiated ATP there was no difference in the quantity of product produced from the tritiated acid or the clabeled acid no clear sex difference was found in activity of the enzyme nor was an appreciable difference noted in activity of the enzyme between mature and immature animals

3|46|53|75

preparations|liver|liver|substrate

properties of the phenobarbital induced cytoplasmic aldehyde dehydrogenase ec have been studied in rat liver fold higher C2 were seen in the cytoplasmic activities after phenobarbital treatment in reactor compared to nonreactor animals with high concentrations of acetaldehyde mm and propionaldehyde mm no difference was found with mm acetaldehyde mm glycolaldehyde mm formaldehyde or mm betaine aldehyde the reactor group also had slightly higher activity in the mitochondrial fraction with the high acetaldehyde and propionaldehyde concentrations in the microsomal fraction the activities showed no differences at any substrate concentration an induced aldehyde dehydrogenase was purified fold by chromatographic techniques it had different molecular and enzymic properties than the main highkm enzyme normally present in rat liver cytoplasm the pi of the induced enzyme was about as measured by isoelectric focusing it was active with several aliphatic and aromatic aldehydes but not with formaldehyde glycolaldehyde or dglyceraldehyde the kmvalues for propionaldehyde and acetaldehyde were in the millimolar range millimolar concentrations of aromatic aldehydes caused a strong substrate inhibition the enzyme was inhibited by submicromolar concentrations of disulfiram estrone deoxycorticosterone progesterone and DES also affected the CEA

17|180|184

levels|diethylstilbestrol|enzyme activity

the hydrolysis of pnitrophenyl phosphate by wheat germ acid phosphatase orthophosphoric monoester phosphohydrolase ec has been investigated in mixtures of AQ buffers with AC dioxane and acetonitrile the enzyme was either in free solution or immobilized on a pellicular support which consisted of a porous carbonaceous layer on solid glass beads the highest enzyme activity was obtained in AC and acetonitrile mixed with citrate buffer over a wide range of organic solvent concentration in vv acetone both v and km of the immobilized enzyme were about half of the values in the neat AQ buffer but the ki for inorganic phosphate was unchanged in vv mixtures of various solvents and citrate buffers of different ph the enzymic activity was found to depend on the ph of the AQ buffer component rather than the ph of the hydroorganic mixture as measured with the glasscalomel electrode the relatively high rates of pnitrophenol liberation in the presence of glucose even at high organic solvent concentrations suggest that transphosphorylation is facilitated at low water activity

20|23|58|93|127

aqueous|acetone|acetone|aqueous|aqueous

a strain of bacillus sp bacillus r produces a protease and a carbohydrolase both of which have the ability to lyse rhizopus cell walls of the enzymes the carbohydrolase has been purified to an ultracentrifugally and electrophoretically homogeneous state and identified as a chitosanase the enzyme was active on glycol chitosan as well as chitosan molecular weight of the purified enzyme was estimated as and isoelectric point as ph the enzyme was most AS at ph and at degrees c with either rhizopus cell wall or glycol chitosan as substrate and was stable over a range of ph to at degrees c for h the activity was lost by sulfhydryl reagents and restored by either reduced glutathione of lcysteine an abrupt decrease in viscosity of the reaction mixture suggested an endowise cleavage of chitosan by this enzyme

73

active

OS containing terminal nonreducing alpha leads to alpha leads to and alpha leads to linked mannose residues isolated from human and bovine mannosidosis urines were used as substrates to test the specificities of acidic alphamannosidases isolated from human and bovine liver the enzymes released all the alphalinked mannose residues from each oligosaccharide and were most effective on the smallest substrate enzyme a in each case was less AS on the oligosaccharides than alphamannosidase b even though the apparent km value for the substrates was the same with each enzyme the human acidic alphamannosidases were also found to be more active on substrates isolated from human rather than bovine mannosidosis urine human alphamannosidase c which has a neutral ph optimum when assayed with a synthetic ATP did not hydrolyse any of the oligosaccharides at neutral ph but was found to be active at an acidic ph

0|67|124

oligosaccharides|active|substrate

the characterization and localization of a caatpase atp phosphohydrolase ec in the tooth germ of the porcine fetus are reported this enzyme a microsome fraction is preferentially activated by ca in the presence of mm atp maximal CEA is obtained at mm cacl the maximal rate of atp hydrolysis is approx mumol per h per mg of protein as the enzyme preparation is used here at optimal ca concentration the mg has an inhibitory effect the enzyme does not require na orand k for activation by ca other nucleotide triphosphates may serve as the substrate but v for atp is the highest the km for atp is m the optimal ph for ca activation of the enzyme lies around well known inhibitors of na katpase mitochondria atpase and caatpase in the erthrocyte do not inhibit the enzyme in the subcellular order the enzyme may be assumed to be localized in the SER fraction containing cell and golgi body membrane fragments and in the tissue order in the enamel organ containing an ameloblast SL stratum intermedium and stellate reticulum

37|151|172

enzyme activity|smooth endoplasmic reticulum|layer

purified skeletal muscle myosin ec has been covalently bound to sepharose b by the cyanogen bromide procedure the resulting complex sepharosemyosin possesses adenosine triphosphatase activity and is relatively stable for long periods of time under optimal binding conditions approximately of the TPS atpase activity of the bound S1 is retained PAGE of polypeptides released from denatured sepharosemyosin indicates that of the myosin is attached to the agarose beads through the HCs and the remainder through the light chains in PA with predictions of IB and PR based upon either the lysine contents or molecular weights of themyosin subunits the adenosine triphosphatase of the immobilized S1 has been investigated under conditions of varying ph ionic strength and cation concentration the atpase profiles of immobilized myosin are quite similar to those for free myosin however subtle differences are found the sepharosemyosin atpase is not as sensitive as myosin to alterations in salt concentration and the apparent km is approximately twofold higher than that of myosin these differences are probably due to chemical modification in the region of the attachment sites to the agarose beads and hydration and diffusion limitations imposed by the polymeric agarose matrix

41|47|50|70|79|83|85|104

specific|myosin|polyacrylamide gel electrophoresis|heavy chains|agreement|binding|release|myosin

based on incorporation of radioactively labeled nethylmaleimide the readily reactive thiol groups of isolated myosin ec from fast slow and cardiac muscles could be classified into types all myosins contain thiol thiol and a variable number of thiol groups per molecule both thiol and thiol CG which are essential for SF-36 of the kstimulated atpase are located in the HCs in all myosin types the R2 in the incorporation pattern of nethylmaleimide over the thiol group classes under steadystate conditions of mg atp hydrolysis allowed different conformations of some reaction intermediates to be characterized in all types of myosin the hydrolytic cycle of mg atp was found to be controlled by the same step at degrees c in all three cases this ratelimiting step is changed in the same way by lowereing temperature using the chemically determined molecular weights for myosin light chains their stoichiometry was found on the basis of sodium dodecyl sulfate electrophoresis to be for CS chain light chainlight chain per molecule of fast S1 for light chainlight chain per molecule of slow S1 and for light chainlight chain per molecule of CM this qualitative difference in light subunit composition between the fast and the two types of slow myosin is not reflected in the small variations of the characteristics exhibited by the isolated myosins but rather seems to be connected with their respective myofibrillar atpase activities

45|50|59|65|158|167|176|185

groups|functioning|heavy chains|variation|light|myosin|myosin|cardiac myosin

the ph dependencies of the apparent K(m) for oxidized glutathione and the apparent turnover number of yeast glutathione reductase ec have been determined at a fixed concentration of mm nadph in the range ph between ph and both of these parameters are relatively constant the principal effect of low ph on the kinetics of the enzymecatalyzed reaction is the observation of a phdependent ATP inhibition by Ox glutathione at ph less than or equal which is shown to correlate with the IB of oxidized glutathione to the oxidized form of the enzyme the catalytic activity of yeast glutathione reductase at ph is affected by the sodium acetate buffer concentration the stability of the oxidized and reduced forms of the enzyme at ph and degrees c in the absence of bovine SS albumin was studied as a function of sodium acetate concentration the results show that activation of the catalytic activity of the enzyme at low sodium acetate concentration correlates with an effect of sodium acetate on a reduced form of the enzyme in contrast inhibition of the catalytic activity of the enzyme at high sodium acetate concentration correlates with an effect of sodium acetate on the GSSG of the enzyme

6|63|66|81|130|196

michaelis constant|substrate|oxidized|binding|serum|oxidized form

the phosphorylated form of CL glycogen phosphorylase alphaglucan orthophosphate alphaglucosyltransferase ec phosphorylase a is AS and easily measured while the dephosphorylated form phosphorylase b in contrast to the muscle enzyme has been reported to be essentially inactive even in the presence of amp we have purified both forms of phosphorylase from rat liver and studied the characteristics of each phosphorylase b activity can be measured with our assay conditions the phosphorylase b we obtained was stimulated by high concentrations of sulfate and was a substrate for muscle phosphorylase kinase whereas phosphorylase a was inhibited by sulfate and was a ATP for liver phosphorylase phosphatase substrate IB to phosphorylase b was poor km glycogen mm glucosep mm compared to phosphorylase a km glycogen mm km glucosep mm CL phosphorylase b was AS in the absence of amp however amp lowered the km for glucosep to mm for purified phosphorylase b and to mm for the enzyme in CE ka mm using AGA substrate buffer and amp concentrations assay conditions have been developed which allow determination of phosphorylase a and of the phosphorylase b activity in liver extracts interconversion of the two forms can be demonstrated in vivo under acute stimulation and in vitro with little change in total activity a decrease in total phosphorylase activity has been observed T3 prolonged starvation and in diabetes

4|14|99|105|126|130|156|160|217

liver|active|substrate|binding|liver|active|crude extract|appropriate|after

two rb EA CS kinases gtpcasein kinase i and gtpcasein kinase ii have been purified and fold respectively studies employing sucrose density gradient centrifugation indicate that kinase i has a molecular weight of about s and kinase ii about s these enzymes can utilize either atp or gtp as the phosphoryl donor among various protein substrates examined these kinases catalyze the phosphorylation of CS greater than dephosphorylated phosvitin congruent to dephosphorylated casein greater than phosvitin histones protamine and bovine SS albumin are poor phosphoryl acceptors kinetic data indicate that both enzymes are inhibited by high CS substrate concentrations which may be partially relieved by nacl both phosphotransferases require mg for activity and are optimally AS at ph the enzymes have apparent km values of m for gtp m for atp and mgml for CS the incorporation of the terminal phosphate of gtp into casein as catalyzed by these enzymes is inhibited to varying degrees by atp itp adp and gdp but not by utp ctp gmp adenosine cyclic monophosphate and guanosine cyclic monophosphate in addition naf and diphosphoglyceric acid are also found to inhibit the activity of both kinases the effect of 2,3-DPG is interesting and suggests that this metabolite may regulate the activity of the CS kinases in the red blood cells

1|2|3|63|79|95|114|133|192|206

rabbit|erythrocyte|casein|casein|serum|casein|active|casein|diphosphoglycerate|casein

a purification procedure for creatine kinase ec from muscle of the monke muequiv hmg protein per min at degrees c and a yield of approx gkg muscle assuming equilibrium kinetics synergistic binding of substrates at one catalytic site is found for both the forward and back reactions kinetic constants for the binding of each ATP to the free enzyme and the enzymesecond substrate complex are determined and are compared with those for the enzyme from other species inhibition by small anions is determined in the presence of different combinations of substrates and products so inhibits by simple competitive inhibition and probably binds at the site of the transferrable phosphoryl group inhibition by no no scn and cl is more complex and these ions are suggested to mimic the transferrable phosphoryl group in a planar transitionstate complex these anions stabilize the deadend complex enzymecreatinemgadp which lacks the transferable phosphoryl group the effects of these anions on the dissociation constants of the ES complexes is reported and is in accord with the above hypothesis the deadend complex in the absence of anion does not protect the essential thiol group against inhibition by iodoacetamide addition of no or cl to the deadend complex or a ATP equilibrium mixture without anion confers protection the essential thiol group is inhibited by iodoacetamide at a rate which is essentially independent of ph over the normal stability range of the enzyme contrary to our previous report this ph independence is not altered by the presence of deadend complex creatine plus mgadp in the presence or absence of anion or in the presence of a substrate equilibrium mixture it is inferred that the essential thiol group of the monkey enzyme has essentially the same properties as that of the rabbit enzyme in consequence the inferences made about the role of this group based on our previous work on the monkey enzyme are no longer valid the present findings are compatible with the essential thiol group playing a conformational role in the catalytic process

54|160|202

substrate|enzymesubstrate|substrate

a technique has been developed to separate and measure kallikrein in a heterogeneous population of rat renal cortical cells in suspension T3 rat kidneys were perfused in situ in anaesthetized rats viable counted cortical cell suspensions were obtained cells were suspended in a sucrosetris buffer containing deoxycholate homogenized centrifuged dialyzed and gel filtered on sephadex g column chromatography on deaecellulose resulted in a single peak of esterase activity between to m naclsodium phosphate buffer subsequent elution yielded an alkaline esterase which was identical to kallikrein isolated from rat urine insofar as ph optimum effects of inhibitors bioassay activity and immunological properties were concerned calculated yields were about of the total esterase activity present in the parent cell homogenates recoveries of a purified rat urinary kallikrein added to the cell homogenates the deaecellulose columns or the eluates from the columns ranged from mean using this technique it was found that the amount of kallikrein activity present in nonincubated renal cortical cells ranged from to alphantosyllarginine methyl ester tosargome esterase units per cells however cells incubated in a nutrient medium at degrees c for h contained no measurable kallikrein activity whereas the surrounding medium had kallikrein activity which could be significantly increased by aldosterone and decreased by spironolactone

21

after

the electrochemical behaviour of ferricytochrome c metmyoglobin and methemoglobin was studied using dc ac and differential PP polarography and controlled potential electrolysis the three hemoproteins yield dc polarographic steps and peaks in differential pulse polarograms the height of which is proportional to concentration the charge transfer is influenced by strong adsorption the concentration dependence of the ac polarograms indicates structural changes in the adsorbed molecules the reduction products of controlled potential electrolysis of metmyoglobin and methemoglobin have absorption spectra identical with the native control samples the affinity for oxygen and the cooperativity in hemoglobin are not affected by the reaction at the electrode the charge transfer proceeds via adsorbed already reduced molecules to freely diffusible proteins

16

pulse

theory is presented relating to the binding of an effector to two states of a protein acceptor coexisting in equilibrium the problem is treated in terms of the four possible cases which specify relations between numbers of binding CS and intrinsic binding constants relevant to the acceptor states it is shown that a distinction between these cases may be possible on the basis of the form of a plot of unbound effector concentration versus the constituent equilibrium coefficient which may be calculated from the sedimentation coefficient of the protein constituent particularly noteworthy in this respect is the finding that a turning point may exist in this plot for defined conditions with systems in which IB CS are not conserved and binding affinities are altered on polymer formation the latter type of system is exemplified by studies on methaemoglobin a in m sodium acetate ph in the absence of added organic phosphate effectors a dimertetramer equilibrium operates governed by an association constant of x mol determined from sedimentation equilibrium results correlation of sedimentation velocity and equilibrium results shows that addition of adenosine triphosphate atp results in its binding to one site on each of the dimeric alpha beta and tetrameric alpha beta species with intrinsic binding constants and mol respectively it is also shown that 2,3-DPG perturbs the dimertetramer equilibrium in a similar way to atp

38|114|115|214

sites|binding|sites|diphosphoglycerate

human hemoglobin was spin labeled with isothiocanatotetramethylpiperdinooxyl which is known to bind specifically to the nterminal alphaamino CG of proteins and slightly to the reactive sulfhydryl groups electron spin resonance esr analysis indicated a partially resolved fiveline spectrum suggesting that the label was attached to at least two different IB sites using specific blocking reagents prior to spin labeling the two IB CS were attributed to the sulfhydryl group of beta immobile and the alphaamino group of the nterminal valines mobile the relative motion of the spin at one set of binding sites was restricted regardless of the state of ligation and ph while the motion at the other site showed dependence on those parameters eg the spinlabeled NT ends of deoxyhemoglobin have restricted motion at all ph ranges studied while those of oxyhemoglobin are relatively free to move at the basic ph range but become more restricted in the acidic ph range

17|49|61|62|118

groups|binding|binding|sites|nterminal

the erythrocruorin of the leech haemopis grandis possessed an sw of s at neutral ph its isoelectric point at ph and exhibited a slightly sigmoid oxygenation curve with n approximately and p mm at ph a minimum molecular weight of per heme group was determined from the iron and heme contents and weight respectively the subunit composition of the erythrocruorin was investigated using gel filtration in sodium dodecyl sulfate and SDS-PAGE at neutral ph haemopis erythrocruorin dissociated in the presence of sodium dodecyl sulfate into four subunits through possessing molecular weights of about and respectively when the erythrocruorin was reduced with mercaptoethanol prior to sodium dodecyl sulfate electrophoresis three subunits were observed possessing molecular weights of about i ii and iii sodium dodecyl sulfate electrophoresis of the isolated subunits through showed that S1 i was provided by subunits and subunit ii was provided by subunit and subunit iii was provided by both subunit and subunit haemopis erythrocruorin thus appeared to consist of at least five different polypeptide chains it is likely that not all of the constituent polypeptide chains were associated each with a heme group the shape of the haemopis erythrocruorin observed by electron microscopy appeared to be consistent with the twotiered hexagonal array characteristic of annelid erythrocruorins and chlorocruorins

70|132

polyacrylamide gel electrophoresis in sodium dodecyl sulfate|subunit

the contractile proteins from arterial smooth muscle are highly soluble and can be extracted at i however they can be precipitated by a prolonged dialysis at ph to give an actomyosin with a high although variable actinmyosin ratio the sedimentation behavior of this actomyosin at high ionic strength was examined as a CF of ph protein concentration and composition by preparative ultracentrifugation comparisons with synthetic skeletal muscle actomyosins of similar composition demonstrated significant differences in the behaviors of these two systems it was found that much smooth muscle AM is not dissociated by normally relaxing conditions and that it sediments at a slower rate than factin the solubility of the supernatant protein a myosinenriched actomyosin in m k cl ph depended on the ph during centrifugation a lower solubility was associated only with a higher actin concentration in the supernatant suggesting a dependence on actin repolymerization pure myosin was selectively precipitated from the supernatant by polyethylene glycol but only when the protein was soluble at low ionic strength the solubility of purified S1 was similar to that of myosin from striated muscles a relationship between the presence of depolymerized actin and the high solubility of smooth muscle contractile proteins is suggested

52|88|172

function|actomyosin|myosin

the activities of hybrid dimers of alkaline phosphatase containing two chemically modified subunits have been investigated one hybrid species was prepared by dissociation and reconstitution of a mixture of two variants produced by chemical modification of the native enzyme with succinic anhydride and tetranitromethane respectively the succinylnitrotyrosyl hybrid was separated from the other members of the hybrid set by deaesephadex chromatography and then converted to a succinylaminotyrosyl hybrid by reduction of the modified tyrosine residues with sodium dithionite a comparison of the activities of these two hybrids with the activities of the succinyl nitrotyrosyl and aminotyrosyl derivatives has shown that either the subunits of ALP phosphatase CF independently or if the subunits turnover alternately in a reciprocating mechanism then the intrinsic activity of each subunit must be strongly dependent on its partner subunit

104|106

alkaline|function

fragments of isolated rat liver plasma membrane possess a ribonuclease activity which at ph in the presence of mm edta can digest polyuridylic acid polyu and polycytidylic acid polyc but not polyadenylic acid polya and polyguanylic acid polyg under these conditions the membrane preparation does not degrade native or denatured dna the products of the reaction with polyu mm edta present can be separated on deaesephadex into oligonucleotides of increasing chain length most of the products are di to hexanucleotides which contain terminal phosphate CG when edta is not present ph or the plasma membrane preparation degrades both polya and polyu with polya the product is all nucleoside while with polyu as ATP most of the product is nucleoside but also some oligonucleotides are produced the ribonuclease releases acid soluble products very slowly from high concentrations of polyu mgml UR trinucleotide with and without a terminal phosphate group is degraded by rat liver plasma membrane the trinucleotide diphosphate is rapidly hydrolyzed to nucleoside while the CAG itself is slowly digested and yields intermediate products including nucleoside

84|112|139|165

groups|substrate|uridine|trinucleotide

the na kactivated mgdependent atpase from rabbit kidney outer medulla was prepared in a partially inactivated soluble form depleted of endogenous phospholipids using deoxycholate this preparation was reactivated to fold by sonicated liposomes of phosphatidylserine but not by nonsonicated phosphatidylserine liposomes or sonicated phosphatidylcholine liposomes the reconstituted enzyme resembled native membrane S9 of na katpase in its ph optimum being around showing optimal activity at mgatp mol ratios of approximately and a km value for atp of mm arrhenius plots of this reactivated activity at a constant ph of and an mg atp mol ratio of showed a discontinuity sharp change of slope at degrees c with activation energy ea values of kcalmol above this temperature and kcal below it a further discontinuity was also found at degrees c and the ea below this was very high greater than kcalmol increased mg concentrations at mgatp ratios in excess of inhibited the na katpase activity and also abolished the discontinuities in the arrhenius plots the addition of cholesterol to phosphatidylserine at a mol ratio partially inhibited na katpase reactivation arrhenius plots under these conditions showed a single discontinuity at degrees c and ea values of and kcalmol above and below this temperature respectively the ouabaininsensitive mgatpase normally showed a linear arrhenius plot with an ea of kcalmol the cholesterolphosphatidylserine mixed liposomes stimulated the mgatpase activity which now also showed a discontinuity at degrees c with however an increased value of kcalmol above this temperature and kcalmol below kinetic studies showed that cholesterol had no significant effect on the km values for atp since both cholesterol and mg are known to alter the effects of temperature on the fluidity of phospholipids the above results are discussed in this context

51

preparations

a preparation of atpase from the CM of micrococcus lysodeikticus solubilized and more than pure showed two main bands in analytical polyacrylamide gel PACE they did not correspond to isoenzymes because one band could be converted into the other by exposure to a mildly ALP ph value the conversion was paralleled by changes in molecular weight circular dichroism and catalytic properties denaturation by ph at degrees c was followed by means of circular dichroism ultracentrifugation and PAGE a C1 conformational transition took place in the acid range with midpoints at about ph i m i m and i m the transition was irreversible strong aggregation of the protein occurred in this range of ph the final product was largely random coil but even at ph dissociation into individual subunits was not complete however partial dissociation took place at ph i m at this ph value the enzyme was inactive but of the activity could be recovered when the ph was returned to in the ALP region the midpoint of the transition occurred near ph i m the pk of most of the tyrosine residues of the protein was about the unfolding was irreversible and the protein was soon converted into peptide species with molecular weights lower than those determined for the subunits by gel electrophoresis in the presence of sodium dodecyl sulphate conventional proteolysis did not account for the transformation

6|23|44|76|78|164

membranes|electrophoresis|alkaline|polyacrylamide gel electrophoresis|large|alkaline

the helix to coil transition of polylglutamic acid was investigated in and m aqueous potassium chloride solutions by use of potentiometric titration and circular dichroism measurement polymer concentration dependence of the transition was observed in the range from to monomole in m kg solution the polymer concentration dependence can be interpreted by current theories of the transition of charged polypeptides and of titration curves of linear weak polyelectrolytes taking the effect of CP concentration into consideration

72

polymer

experiments were conducted on cats under nembutal anesthesia a study was made of PP activity of bulbar respiratory neurons EA of the diaphragm and of the IC muscles po pco ph arterial blood oxygen saturation were determined in combined action of hypoxia and hypercapnia when hypoxic gaseous mixture was given for respiration the developing hypocapnia disturbed the discharge rhythmic activity of the respiratory neurons the respiration acquiring a pathological character of the cheynestokes type after addition to the hypoxic gaseous mixture of co the gaseous composition of the arterial blood approached the initial values this addition prevented the OD of hypercapnia and disturbances of rhythmic discharge activity of the respiratory neurons addition of co to the hypoxic gaseous mixture produced a negative effect at first it intensified and then depressed the PP activity of the respiratory neurons caused metabolic and respiratory acidosis and promoted asphyxia

13|19|26|98|131

pulse|electrical activity|intercostal|development|pulse

experiments were conducted on male rats a study was made of the content of nicotinamide coenzymes in the liver and myocardium hours after the administration of ml of dichloroethane into the stomach in parallel with disturbance of the morphological structure of the CL and of the myocardium increase in the activity of alanine and aspargic aminotranspherases in the blood SS dichloroethane reduced the content of nicotinamide coenzymes and deranged the ratio of their oxidized and reduced forms in these organs

42|59

liver|serum

chronic experiments were conducted on rats and rabbits a study was made of the effect of carbidine on the CS defence reflexes in stimulation of the mesencephalic part of the reticular formation carbidine prevented the depression of the conditioned defence reflexes caused by stimulation of the mesencephalic portion of the Rt formation this pointed to its depressive influence on the mentioned structures and was confirmed by experiments on rabbits in recording changes in biocurrents under conditions of stimulation of the mesencephalic reticular formation

19|50

conditioned|reticular

it was shown in acute experiments on rats that one hour after an intraperitoneal injection of theophylline mgkg there was a decrease in the nad nadp content by a tendency to a fall of nadh nadph was expressed and the total nicotinamide coferment level was reduced a tendency to decrease nad nadp and the total pyridine nucleotide level was seen after caffeine administration the action of catecholamines and methylxanthines was compared theobromine produced no significant effect on the indices under study it was shown that isadrine decreased the nad nadp level adrenaline mkgkg increased the content of both the Ox by and of the reduced by forms of pyridine nucleotides an increase of adrenaline dose to mkgkg was accompanied by reduction of the oxidized forms by and of the total nicotinamide coferment level by

99

oxidized

drinking water supplies of rural communities in georgetown county south carolina were randomly selected for sample collection the analysis showed that most of the waters were slightly acidic low but acceptable concentrations of chloride copper fluoride sodium cadmium nitrate and phosphate were found a few water samples showed higher then recommended levels of arsenic mercury zinc and lead although only of the samples exceeded the mandatory limit of ppm for As exceeded the recommended level of ppm the mandatory limit for manganese was exceeded in of the waters while exceeded the limit for iron the high iron content was generally responsible for the high turbidity found in of the samples the well depth and the consumer income had some bearing on water SQ statistical evidence suggested that septic tank seepage was partially responsible for nitrate phosphate iron and arsenic contamination of shallow water supplies lead concentrations appear to vary according to the plumbing used and the ph of the waters

70|122

arsenic|quality

this T0 has investigated the relationship between duodenogastric reflux gastritis and certain PS months T3 three operations for uncomplicated duodenal ulcer the operations studied were proximal gastric vagotomy pgv cases TV and pyloroplasty tvp cases and TV and antrectomy tva cases duodenogastric reflux was assessed both by a radiological technique and by measuring the concentration of bilirubin in the gastric aspirate before and after operation incidence and severity of postoperative gastritis were determined by endoscopic biopsy PS were assessed by symptomatic score and visick grading there was a significant correlation between duodenal reflux and histological evidence of both severe SG and glandular atrophy p less than there was also a close association between the degree of reflux and the presence of severe heartburn epigastric pain and bile vomiting after operation the amount of reflux did not differ before T0 there was significantly less reflux following pgv than after either tvp p less than or tva p less than the results indicate that an operation which preserves an innervated and IN antrum and pylorus will protect against postoperative duodenogastric reflux gastritis and symptoms

1|12|14|30|36|76|99|138|169

study|symptoms|after|truncal vagotomy|truncal vagotomy|symptoms|superficial gastritis|operation|intact

a new haemoglobin with increased oxygen affinity beta ef lysine leads to threonine hb rahere was found during the investigation of a patient who was found to have a raised haemoglobin concentration after a routine blood count the substitution affects one of the 2,3-DPG IB sites resulting in an increased affinity for oxygen but both the haemhaem interaction and the alkaline bohr effect are normal in the haemolysate this variant had the same mobility as haemoglobin a on PACE at alkaline ph but was detected by measuring the whole blood oxygen affinity it could be separated from haemoglobin a however by electrophoresis in agar at acid ph the raised haemoglobin concentration was mainly due to a reduction in CPV a relative polycythaemia and was associated with a persistently raised white blood count this case emphasises the need to measure the oxygen affinity of haemoglobin in all patients with absolute or relative polycythaemia when some obvious cause is not evident

43|44|78|118

diphosphoglycerate|binding|electrophoresis|plasma volume

the actions of glycine gaba alphaalanine betaalanine and taurine were studied by intracellular recordings from lumbar MNs of the isolated spinal cord of the frog all amino acids tested produced a reduction in the amplitude of postsynaptic potentials a blockade of the antidromic action potential and an increase of Gm furthermore membrane polarizations occurred which were always in the same direction as the ipsp all these effects indicate a postsynaptic GABA action of these amino acids when the relative strength of different amino acids was compared taurine had the strongest inhibitory potency followed by betaalanine alphaalanine gaba and glycine topically applied strychnine and PT induced different changes of postsynaptic potentials indicating that distinct GABA systems might be influenced by these two convulsants interactions with amino acids showed that picrotoxin seletively diminished the postsymaptic actions of gaba while strychnine reduced the effects of taurine glycine alpha and betaalanine but differences in the susceptibility of these amino acid actions to strychnine could be detected the action of taurine was more sensitively blocked by strychnine compared with glycine alpha and betaalanine with regard to these results the importance of taurine and gaba as transmitters of postsynaptic inhibition on motoneurons in the spinal cord of the frog is discussed

16|49|70|103|113

motoneurons|membrane conductance|inhibitory|picrotoxin|inhibitory

crude synaptosomal fractions p derived from guineapig cerebral SC were incubated in the presence of mm kcl in a krebsglucose medium torpedo marmorata electric organs were stimulated electrically in vivo at pulsessec for min by electrodes placed on the electric lobe SVs were isolated from each source and the phospholipid compositions analysed and compared with vesicles from unstimulated controls lysophosphatidylcholine was the only lysophosphoglyceride demonstrable in the synaptic vesicles from either source and its low levels did not increase as a result of chemical or electircal stimulation in each case there was a close similarity of the phospholipid distributions in the vesicles taken from control and stimulated samples control experiments indicated extensive decreases in the acetylcholine content of the vesicles from the stimulated EO and smaller decreases in the acetylcholine content of the synaptic vesicles from stimulated P2 fractions these fractions were found to respire linearly in the presence of mm glucose and the vesicle fractions were shown to have low levels of contaiminating membranes as judged by marker enzyme analyses crude synaptosomal fractions from guineapig CBF cortex were incubated in a krebsglucose medium with labelled fatty acids and hglucose in the presence or absence of mm kcl subsynaptosomal fractionation was carried out and specific radioactivities of phosphatidylcholine phosphatidylethanolamine phosphatidylserine and phosphatidylinositol were determined in fractions d SVs e microsomes and h disrupted synaptosomes the release of neurotransmitter did not significantly enhance the labelling of phospholipids in any of the fractions studied as compared with phospholipids from unstimulated fractions this was found T3 two incubation times and using coleate carachidonate hpalmitate and hglucose

8|41|123|137|176|217|252

cortex|synaptic vesicles|electric organ|crude synaptosomal|cerebral|synaptic vesicles|after

the effects of acidbase changes on cardiac output during diethyl ether anaesthesia were studied in mongrel dogs prepared by surgically implanting a plastic encased nonferrous core EM probe on the ascending aorta the findings are metabolic acidaemia produced only slight decrease in cardiac output but a more marked fall became evident with decreasing ph respiratory acidaemia led to a slight rise in cardiac output respiratory alkalaemia decreased cardiac SO metabolic alkalaemia also produced a decline in cardiac output

26|68

electromagnetic|output

many eyes donated for use in corneal grafting are rejected because of signs of autolysis in the donor material the purpose of this experimental study was to determine whether hydrocortisone acting as a lysosome membrane stabilizer could prevent or retard autolysis of the corneas under storage and if so what was the most efficacious concentration different groups of rb corneas were placed in saline as controls or in varying concentrations of hydrocortisone m to m at ph at degrees c and degrees c acid phosphatase released T3 six hours was measured biochemically this enzyme was used as a marker enzyme reflecting lysosomal labilization results showed a significant stabilization of the lysosomal membrane at degrees c as compared to degrees c a trend towards stabilization of the lysosomal membrane was seen when m concentration of hydrocortisone at degrees c was used there being no demonstrable stabilization at degrees c

58|86

rabbit|after

mock cerebrospinal fluid ph or dinitrophenol dnp mg was injected into the subarachnoid space of the ventral brain stem of exteriorized fetal sheep changes in ph on the ventral surface of the medulla did not stimulate respiratory efforts or induce significant cardiovascular changes the respiratory response to dnp injections ranged from no response to prolonged rhythmic ventilation that was independent of the IP chemoreceptors or the control arterial ph and blood gas tensions this inconsistency suggests an effector site somewhat removed from the immediate surface of the medulla the heart rate and blood pressure were not affected it is concluded that increased h concentration in the extracellular fluid of the fetal ventral medulla does not initiate respiration and any respiratory response to metabolic inhibitors applied to this area therefore is not attributable to a AA NC in surface ph

62|134|135

peripheral|secondary|change

axenic washed conidia of fusarium solani f sp phaseoli aspergillus flavus and verticillium alboatrum were placed on washed difco purified agar discs along with an inorganic salt solution containing various levels of carbon and nitrogen substrates these discs were exposed to volatiles from six soils ph fusarium solani macroconidial germination was inhibited mostly by volatiles from soils of ph and but high levels of glucose and nhcl reversed this inhibition raising germination to that of nosoil nocarbon or nitrogen controls conidial germination of a flavus was inhibited mainly by volatiles from high ph and soils and increased levels of glucose plus an CAA mixture nullified this inhibition volatiles from soils of ph and stimulated a flavus conidial germination assays after the removal of co from the air above soil of ph demonstrated that volatiles inhibitory to a flavus were produced by this soil assays indicated that a kohsoluble compound was a fungistatic soil volatile to f solani macroconidial germination the nullification by carbon and nitrogen substrates of f solani and a flavus inhibition caused by soil volatiles parallels that for soil fungistasis conidial germination of v alboatrum was markedly stimulated by volatiles in all soils tested and was not affected by removal of co inhibitory soil volatiles may increase the nutritional requirements for spore germination of certain fungi

102

amino acid

earlier work showed that escherichia coli contains at least two enzymes which reduce NF and other nitrofuran derivatives one of these enzymes is lacking in some nitrofurazoneresistant mutant strains we now report that there are three separable nitrofuran reductases in this organism reductase i mol wt approximately insensitive to o reductase iia mol wt approximately inhibited by oxygen reductase iib mol wt approximately inhibited by o unstable metabolites formed during the reduction of nitrofurazone by preparations containing reductases iia and iib produce breaks in dna in vitro in vivo experiments with nitrofurazoneresistant strains which lack reductase ii but contain reductases iia and iib demonstrated that lethality mutation and dna breakage are all greatly increased when cultures are incubated under anaerobic conditions ie conditions such that reductase ii is active these results provide further evidence for the importance of reductive activation of NF

13|141

nitrofurazone|nitrofurazone

the mixture of PSs in the gelling component of agar agarose is hydrolyzed to dgalactose and anhydrolgalactose by a series of hydrolytic enzymes obtained from pseudomonas atlantica the final degradative step in the pathway of agarose decomposition is the hydrolysis of the alphalinkage in the dissaccharide neoagarobiose yielding dgalactose and anhydrolgalactose pseudomonas atlantica when grown on agar produces two specific enzymes pnitrophenyl alphagalactose hydrolase and neoagarobiose hydrolase the purification and partial characterization of both enzymes are presented

3

polysaccharides

significant differences in amylase betaglucosidase and phosphatase activities were observed among four phytophthora cinnamomi isolates grown in nutrientamended sterilized soil for days amylase ph optima for the four isolates were within a relatively narrow range at ph each isolate was within of its peak activity isolates sb and c each exhibited maximal betaglucosidase activity at ph and maximal phosphatase activity at ph maximal activity for these two enzymes of isolate a occurred at ph in timed experiments isolates and a exhibited greater amylase MICs than did the other two isolates for betaglucosidase greatest activity was observed for sb activity of was intermediate and least activity was observed for isolates a and c isolates sb and exhibited greatest phosphatase MICs isolate c was intermediate in activity and a was least active results indicate that significant differences exist among the isolates tested and that these differences can be quantitatively measured by the methods described

83|118

activities|activities

an intracellular invertase was induced in cultures of clostridium pasteurianum utilizing sucrose as its carbon source for growth this enzyme synthesis could be repressed by the addition of fructose of a sucrosegrowing culture in contrast invertase activity was not affected by the addition of glucose to sucrosegrowing cells and this enzyme could be induced in a glucosemetabolizing culture by the addition of sucrose this enzyme was purified fold over the induced lese ec by substratespecificity studies invertase had a ph optimum of and an apparent km of mm for SU and required high concentration of potassium phosphate for maximum activity INV was completely inactivated by a min heat treatment at degrees c this enzyme was strongly inhibited by phydroxymercuribenzoate pcmb and weakly inhibited by dithiobisnitrobenzoic acid while cysteine could substantially reverse pcmb inhibition suggesting that sulfhydryl CG were necessary for invertase activity

89|100|136

sucrose|invertase|groups

the adenosinetriphosphatase atpase ec activity in azotobacter vinelandii concentrates in the membranous r fraction that is directly associated with azotobacter electron transport CF sonically disrupted azotobacter cells were examined for distribution of atpase activity and the highest specific activity and activity units was consistently found in the particulate r membranous fraction which sediments on ultracentrifugation at x g for h when the sonication time interval was increased the membranebound atpase activity could neither be solubilized nor released into the supernatant fraction optimal atpase activty occurred at ph mg ion when added to the CA was stimulatory Vmax always occurred when the mgatp stoichiometry was on a molar ratio at the mm concentration level sodium and potassium ions had no stimulatory effect the reaction kinetics were linear for the time intervals studied min the membranebound atpase in the r fraction was stimulated fold by treatment with trypsin and fractionation studies showed that trypsin treatment did not solubilize atpase activity off the membranous r electron transport fraction the atpase was not cold labile and the temperature during the preparation of the r fraction had no effect on activity overnight refrigeration at degrees c however resulted in a loss of activity as compared with a loss when the r fraction was stored overnight at degrees c a marked inactivation although variable usually about did occur by overnight freezing degrees c and subsequent sonication failed to restore atpase activity this indicates that membrane reaggregation by freezing was not responsible for atpase inactivation the addition of azide ouabain dinitrophenol or oligomycin to the CA system resulted in neither inhibition nor stimulation of the atpase activity the property of trypsin activation and that atpase activity is highest in the r electron transport fraction suggests that its probable PET role is in coupling of electron transport to oxidative phosphorylation

22|93|96|258|291

function|assay|maximal activity|assay|functional

within km of a zinc zn smelter in palmerton PA near the lehigh water gap up to zn by weight has been measured in the o horizon of the soil and up to zn in the a horizon the total numbers of bacteria actinomycetes and fungi measured by dilution plate counts were greatly reduced in the most severely zncontaminated soils compared with control soils the reduction of microbial populations may be a partial cause of the decreased rate of litter decomposition at lehigh gap growth of most bacteria from control sites was reduced by to mum zn most actinomycetes by mum zn and most fungi by to mum zn in thinpablum extract agar tpab all the tested actinomycetes and nonsporeforming bacteria isolated from zncontaminated lehigh gap soils were zntolerant growing normally in media containing mum zn most fungi regardless of source were capable of at least of normal growth at mum zn zinctolerant bacteria actinomycetes and fungi were readily isolated from lowzn soils suggesting that selection for zn tolerance may proceed rapidly acidophilic mortierella species have been selectively eliminated near the smelter apparently because of elevated soil ph peryronellaea glomerata corda goidanich and coniothyrium spp were found only in the highzn soils

9

pennsylvania

the effect of feeding a relatively lowprotein diet containing dab for weeks on the activity of dabazoreductase nitroreductase pnitrobenzoic acid noxidase nndimethylaniline ndemethylase dab cytochrome p nadphcytochrome c reductase betaglucuronidase and arylsulphatase a were studied rapid decreases occurred in the activities of the first six enzymes reaching minimal values at between and weeks activities then increased in all cases to control or nearly control levels this rate of increase was least for cytochrome p at weeks azoreductase activity with the chemotherapeutic agent B6 i as substrate was significantly higher than in control rats early increases occurred in the activities of betaglucuronidase and arylsulphatase a and the activity of the latter never dropped below the control level an investigation was made of the differential effects of dye feeding on some of the enzyme activities in the two major liver lobes and differences were found the effect of phenobarbital pb pretreatment on the dabfed rats was studied at week intervals the MICs of dabazoreductase and of nitroreductase increased throughout the whole period while the activities of the lysosomal enzymes were decreased after FF dab for weeks the effect of pb and methylcholanthrene mc on the activities of dabazoreductase cbazoreductase and components of the azoreductasescytochrome p nadphcytochrome c reductase the cocbazoreductase was not induced by pb or mc and co did not inhibit its reduction its reduction depended only slightly on nadh co caused a greater relative decrease in the activity of dabazoreductase in dyefed animals and also in animals following pb and mc i.c.v. implying a greater role of cytochrome p in dyefed animals

82|159|180|251

cb|activities|feeding|pretreatment

the system involved in the reduction of dibromopropyl aminophenylazolbenzoic acid B6 an agent designed for treating primary CL cell cancer has been demonstrated to be localised mainly in the x g supernatant fraction of rat liver TH it is also present in other organs particularly in the SP dabazoreductase as shown previously is present almost entirely in the microsomal fraction and is found in high concentration only in liver the ph maximum for cbazoreductase implying the importance of the carboxyl group in determining substrate specificity the use of enzyme inhibitors and other additives showed that cb was not axanthine oxidase or DHF reductase its activity was not affected by carbon monoxide phenobarbitone pb or methylcholanthrene mc i.c.v. enhancement of the activity by ferrous ions and fad indicated that at least part of the reduction system could involve a flavoprotein with fad as the prosthetic group the activity of cbazoreductase and methylredazoreductase was reduced by menadione vitamin k cyanide and propylgallate a diaphorase preparation from pig heart reduced both B6 and methylred with both nadph and nadhgenerating systems

10|17|36|47|101|116|168

cb|liver|homogenate|spleen|dihydrofolate|pretreatment|cb

subcutaneous or IA injections of mg of hgcl g body weight markedly depressed hepatic fatty acid synthetase activity of chicks at h postinjection the depression occurred despite the fact that the chicks continued to eat up until the time they were killed under these same conditions the hepatic activity of acetylcoa carboxylase ec was not affected by hgcl while the activity of the mitochondrial system of fatty acid elongation was stimulated when mercaptoethanol was included in the incubation medium for a HP preparation of fatty acid synthetase mum hgcl was required to show definite inhibition of the enzyme when mercaptoethanol was omitted mum hgcl was inhibitory and mum hgcl abolished CEA mm dithiothreitol completely protected the purified FAS preparation from inhibition by mum hgcl when dithiothreitol was added after the addition of enzyme to the mercurycontaining medium protection of the enzyme was not CR dialysis of cytosol fractions from chicks injected with hgcl against vol of m potassium phosphate buffer ph containing mm edta and mm dithiothreitol for h at degrees stimulated the fatty acid synthetase activity of the fractions dialysis of cytosol fractions from noninjected chicks under the same conditions was without effect on FAS activity these data support the hypothesis that the inhibitory effect of hgcl administered in vivo on hepatic fatty acid synthetase activity in chicks is mediated through the interaction of mercury with the sulfhydryl groups of the enzyme

2|81|110|117|143|195

intraabdominal|highly purified|enzyme activity|fatty acid synthetase|complete|fatty acid synthetase

we have observed a high and significant mortality in SH rats compared to normotensive and hypotensive controls in the fifth generation the hypertensive rats exhibited a high frequency of cerebral haemorrhage and periarteritis nodosa

9

spontaneously hypertensive

the influence of the sympathetic nervous system on the cerebral circulatory response to graded reductions in mean arterial blood pressure was studied in anesthetized baboons cerebral blood flow was measured by the xe clearance method and arterial blood pressure was decreased by controlled hemorrhage in normal baboons the constancy of cerebral blood flow was maintained until mean arterial blood pressure was approximately of the baseline value thereafter CBF blood flow decreased when arterial blood pressure was reduced superior cervical sympathectomy of weeks duration did not affect the normal response in contrast both acute surgical sympathectomy cervical trunk division and alphareceptor blockade mgkg of phenoxybenzamine enhanced the maintenance of CBF blood flow in the face of hemorrhagic hypotension in that CBF blood flow did not decrease until mean arterial blood pressure was approximately of the baseline value the results indicate that the sympathetic nervous system is not involved in the maintenance of CBF blood flow in the face of a fall in arterial blood pressure indeed the implication is that the sympathicoadrenal discharge accompanying HH is detrimental to rather than responsible for CBF autoregulation

67|108|119|151|173|181

cerebral|cerebral|cerebral|cerebral|hemorrhagic hypotension|cerebral

an isolated perfused canine lung preparation in which determinants of vascular caliber could be individually controlled was developed the relation of pulmonary arterial pa A-V pv and alveolar pa pressures was such that pa greater than pa greater than pv throughout the whole lung the addition of isoprenaline to the perfusate abolished vascular reactivity once stability was reached vascular crosssectional area remained acceptably constant for hours as judged by normalized conductance the influence of perfusate hematocrit blood gas tensions and ph on pressureflow relations was then studied in isolated canine lungs the hematocritvascular conductance relation was derived at constant perfusion pressure conductance varied linearly with hematocrit over a range of to mean pulmonary ABG tensions were po mm hg pco mm hg and ph acute respiratory acidosis po mm hg pco mm hg ph and LA and hypoxemia po mm hg pco mm hg ph did not significantly alter this relation transformation of the conductancehematocrit data indicated that hematocrit was the most important determinant of relative apparent viscosity of the blood both acute respiratory and LA failed to significantly increase relative viscosity within the range of hematocrit usually found in secondary polycythemia

24|113|135|175

venous|arterial blood gas|lactic acidosis|lactic acidosis

the interaction of chemoreflex and pulmonary inflation reflex control of the coronary circulation was examined in conscious dogs by comparing the responses to chemoreflex stimulation intracarotid injection of nicotine when ventilation was allowed to increase with those when ventilation was controlled the responses were also compared with those elicited by both forced mechanical and spontaneous hyperinflation when the HR rate was constant intracarotidly po nicotine induced an increase in the depth of respiration followed closely by an increase in late diastolic CF from to mlmin and a reduction in late diastolic coronary resistance from to mm hgml min after betareceptor and cholinergic blockade a similar coronary dilation in response to nicotine occurred only when ventilation was allowed to increase however when ventilation was controlled intracarotidly administered nicotine increased coronary resistance T3 combined betareceptor and ACh blockade the reflex coronary dilation was not observed after CSN nerve section or after alphareceptor blockade thus nicotine stimulation of the carotid chemoreflex results in a striking coronary dilation that has two components the minor component involves a chemoreflex with its efferent pathway in tthe vagi the major component of coronary dilation follows an increase in the depth of respiration and its efferent component appears to involve withdrawal of alphaadrenergic constrictor tone an almost MZ period of reflex coronary dilation followed either forced mechanical or spontaneous hyperinflation in the conscious dog

58|63|81|130|134|144|209

heart|administered|coronary flow|after|cholinergic|carotid sinus|identical

the rate of coronary blood flow was varied in isolated working rat heart preparations to determine its influence on the rate of glocose utilization tissue highenergy phosphates and intracellular ph a reduction in coronary blood flow resulted in a reduction in oxygen consumption an accelerated rate of glusoe utilization lower tissue levels of highenergy phosphate and higher tissue levels of lactate and h ventricular performance deteriorated as reflected by a decrease in heart rate and PSP further reductions in coronary blood flow resulted in inhibition of glycolysis a greater decrease in tissue C2 of highenergy phosphates and higher tissue levels of both lactate and h these changes in glycolytic flux tissue metabolites and VVI performance were proportional to the degree of restriction in coronary blood flow the importance of coronary blood flow and washout of the interstitial space in the maintenance of accelerated glycolytic flux in oxygendeficient hearts is emphasized it is concluded that acceleration of atp production from glycolysis can occur only in the marginally ischemic tissue in the peripheral area of tissue supplied by an occluded artery the central area of tissue which receives a low rate of coronary blood flow will have a reduced rate of atp production due to both a lack of oxygen and an inhibition of glycolysis

75|92|113

peak systolic pressure|levels|ventricular

the mechanisms of glycolytic inhibition in ICM myocardium were investigated in the isolated perfused rat heart glycolysis was inhibited at the level of G3P dehydrogenase the major factors that accounted for the glycolytic inhibition in the ischemic heart compared with the anoxic heart appeared to be higher tissue levels of lactate and h in the ischemic tissue increased extracellular ph inhibited glycolysis in anoxic and hypoxic hearts much more readily than it did in aerobic hearts however maintenance of both extracellular and intracellular ph caused only a modest acceleration of glycolysis in ischemic hearts accumulation of tissue lactate and inhibition of glycolysis were directly proportional to the reduction in coronary bloow flow in both anoxic and ischemic hearts at intracellular lactate concentrations between and mm glycolysis was inhibited under both conditions addition of either or mm lactate to the perfusate inhibited glycolysis in aerobic anoxic and ischemic hearts the effect of lactate did not appear to be mediated through changes in intracellular ph it is concluded that accumulation of lactate represents a L1 factor in the inhibition of glycolysis that develops in ischemic hearts

6|23|172

ischemic|glyceraldehydephosphate|major

this study compared the contractile performance of a canine RA atrial trabecula with that of a macroscopically indistinguishable trabecula isolated from the RVA the heart was removed from nine mongrel puppies weighing kg and placed in krebsringers bicarbonate solution the bathing solution contained only mmoles of ca and was bubbled with a o co gas mixture each atrial trabecula was specially selected from the right atrial appendage histologically these trabeculae showed a remarkable longitudinal orientation of the fibers at lmax the length of the muscle at which DT was maximum under identical conditions of temperature rate of stimulation ionic milieu ph and o and co supply RA atrial trabeculae achieved the same developed and total tensions but in a much shorter time than did ventricular trabeculae in both muscle groups the maximum developed tension averaged about gmm since lo expressed as a fraction of lmax was less in atrial muscle than it was in ventribular muscle we concluded that atrial muscle can be stretched considerably more than can VVI muscle before optimum length is reached at any given initial muscle length the maximum of tension rise for atrial trabeculae amounted to at least twice that for ventricular trabeculae at any given load up to gmm the maximum velocity of shortening of an atrial trabecula was about three to four times that of a ventricular trabecula these results collectively indicate that the contractile performance of the right atrial muscle is in many respects superior to that of the RA ventricle at least under the conditions of these experiments

9|22|87|106|168|247

right|right ventricular apex|developed tension|right|ventricular|right

the LDH of sera from patients suffering myocardial infarction and of sera from patients with hepatocellular damage was assayed under optimal conditions using pyruvate alphaoxobutyrate hydroxypyruvate and glyoxylate as substrates activity was also measured with lactate as substrate at different ph values the ratios of activities under these different CA conditions were calculated for both series of patients correct differentiations for single ratios ranged from virtually nil for hydroxypyruvatealphaoxobutyrate to is greater than per cent for glyoxylatehydroxypyruvate and glyoxylatealphaoxobutyrate this was little improved by the use of multiple ratios involving up to seven separate assays the activity ratio of hydroxypyruvate to pyruvate which is consistently greater than unity was found to be inverted in a case of morphine poisoning

1|49

lactate dehydrogenase activity|assay

we describe a simple rapid fluorometric assay for separate quantitative analysis of procainamide and nacetylprocainamide in mixtures the effective lenear range fluorescence vs concentration in serum is to mgliter regardless of the ratio by weight of the two drugs from to analytical recoveries by the extraction method used were and respectively for determination of either compound the maximum coefficient of R2 was

60

variation

in this method blood is collected in ammonium heparinized microhematocrit tubes and lactate is directly determined in the plasma separated within min from the erythrocytes lactate is assayed by mixing mul of sample with nad and lactate dehydrogenase in trishydroxymethylaminomethane Hz buffer the rate of increase in absorbance of the nadh formed measured at nm is proportional to lactate concentration the assay is complete in min and absorbance is linearly related to concentration from to mmolliter analytical recoveries of lactate added to plasma averaged range results compared well for plasma samples analyzed by this method with the centrifichem and the du pont aca

40

hydrazine

highvoltage paper PACE of small samples of serum and urine at ph resolves basic and acidic amino acids and separates them from the NAA for separation and ID of the neutral amino acids the appropriate area of the electrophoretogram is cut out sewn onto a second sheet of paper and rerun at ph by this method amino acids are rapidly resolved it is suited for use with special procedures such as oxidation of biological fluid with performic acid and specific IF for confirmation of CAA identification

2|23|27|80|84

electrophoresis|neutral amino acids|identification|staining|amino acid

a simple highly sensitive and reproducible method for the assay of gammaglutamyl transpeptidase ec activity is introduced using gammaglutamylpnitroanilide as a ATP and glycylglycine as an acceptor in gl of polyoxyethylene nonylphenol SS transpeptidase activity was assayed in healthy adults the normal mean value being muml the diagnostic evaluation of the enzyme in various hepatobiliary diseases is also discussed

21|32

substrate|serum

there are different types of renal hypertension hypertension due to parenchymal renal disease renovascular hypertension hypertension due to urological disease hypertension of endstage renal disease treatment has to considerabove allthe possibility of TPS medical or surgical procedures that may cause the underlying condition if the underlying disease is not amenable to specific therapy symptomatic medical treatment to lower blood pressure is indicated besides control of sodiumintake and body weight antihypertensive drugs are generally indicated we use them alone or in combination in the following line of order diuretics betaadrenergic blockers dihydralazine reserpine clonidine alphamethyldopa guanethidine

32

specific

some effects of sodium salicylate upon anaerobic glycolysis have been studied in normal human erythrocytes incubated for up to h at degrees c in autologous sera both glucose consumption and lactate production were stimulated by concentrations of salicylate up to mmoll but at the highest concentration used mmoll an initial CS- was followed by inhibition of glycolysis losses occurred of adenosine triphosphate atp adenosine diphosphate adp and adenosine phosphateampat higher concentrations of salicylate and there was a concomitant increase of inorganic phosphate other phosphate esters underwent concentration changes at higher concentrations of salicylate that reflected inadequate concentrations of atp for glycolysis the rates of sodium efflux from and potassium influx into erythrocytes were unaffected by the presence of salicylate at concentrations sufficient to stimulate glycolysis

50

stimulus

we measured the minute ventilation and arterial blood catecholamine concentrations in four normal men standing and at two C2 of moderate treadmill exercise breathing oxygen or air minute ventilation was significantly higher during hypoxic exercise than during normoxic exercise at an oxygen uptake of mlmin arterial plasma noradrenaline during hypoxic exercise at an oxygen uptake of mlmin was significantly greater than at rest arterial PNA during normoxic exercise at an oxygen uptake of mlmin was not elevated above the resting concentration the results are compatible with the suggestion that increased concentrations of arterial plasma noradrenaline contribute to the hypoxic potentiation of the respiratory response to moderate exercise

18|64

levels|plasma noradrenaline

clinical impressions about the problem of defibrillation during states of acidbase imbalance and hypoxia have been influenced by studies involving the effect of these derangements on the VFT based on body weight energy requirements for defibrillation in normal dogs were compared to requirements in dogs subjected to commonly encountered acidbase disturbances and severe hypoxemia no significant differences were found seventyfive percent of all animals in the T0 were electrically converted with lowtomoderate C2 of SE the incidence of spontaneous resumption of circulation following defibrillation was lowest in animals subjected to metabolic acidosis and hypoxia the results suggest that ph and blood gas alterations previously shown to influence the normal ventricular fibrillation threshold do not significantly affect the normal defibrillation threshold

27|66|72|74

ventricular fibrillation threshold|study|levels|energy

a patient with aortitis syndrome had a pleural effusion which subsided but reappeared with an exacerbation of aortitis PS while under antituberculosis treatment the character of the fluid was that of an exudate and the glucose concentration was normal clinical and laboratory features of the case suggest that the effusion was part of the aortitis syndrome per se

18

symptoms

the apparent isoelectric points pi in isoelectric focusing if of human pituitary and amniotic fluid prolactin hprl both noniodinated and iodinated were determined unresolved mixtures of PIT hprl isohormones e and f and of at least five isohormones found in amniotic fluid and plasma hprl exhibit an average pi value of transient state ph values observed or previously reported for hprl components range from ph to T3 correction to standard conditions at ph the L1 isohormone hprlf carriers a charge of net protons per molecule the net charge differences among isohormones e f and g are compatible with acquisition or loss of single charged groups per molecular weight this net charge is similar to that of the least prolactinbioactive L1 isohormone of human growth hormone hghb while the hgh with a bioactivity comparable to that of hprl exhibits a net charge of valence units the large isohormones j and h increased net charges by a factor of in direct proportion to their size increments

26|66|74|119

pituitary|after|major|major

the feasibility of using isoelectric focusing for the separation of primate pituitary growth hormone from prolactin and for the characterization of polymorphic forms of these hormones was explored in a ph gradient extracts of both human and cynomolgus monkey pituitaries were each resolved into growth hormone components and at least prolactin components as shown by radioimmunoassay in narrower gradients of ph units greater resolution was achieved the principal growth hormone components were well separated from the principal prolactin components but there was overlapping of some minor components a partially purified human prolactin preparation was found to contain prolactin components one of which had a prolactingrowth hormone ratio of clinical grade human growth hormone was also resolved into at least prolactin and growth hormone components many of which had higher pi values than those found in PIT extract under the conditions used both growth hormone and prolactin were found to be polymorphic with respect to isoelectric point some of the human prolactin components were found to contain less than growth hormone by radioimmunoassay monkey growth hormone containing prolactin was isolated these findings demonstrate that isoelectric focusing is useful for the preparation of both growth hormone and prolactin which are essentially free of one another furthermore the polymorphic forms were repeatedly found in S9 obtained by several methods and from different species suggesting that these forms are not artifacts

135|211

pituitary|preparations

certain climatic and edaphic conformations in the bavarian subalpine mountains and in the alps favor above all the development of a land utilization system and farm structures similar to those in the northern part of scandinavia in the years of the highest environmental contamination up to the present we established in beef samples from the round or shoulder of male and female cattle mainly highland cattle close connections between the cscontamination of green crop and the long lastnig yearly precipitation quantities as well as certain relations between the cscontamination of meat and differences in the FF and keeping of the animals during summerseasons apriloctober beef of cattle from pastures with heavy rainfall alps was contaiminated by cs up to times more than that of confined animals hereby the rate of cscontamination in the meat of grazing cattle was nearly proportional to the quantities of precipitation when confined cattle were fed on pastures in autumn after harvesting for to weeks a quick increase of cscontamination of the meat was caused within this time up to values which in this district were otherwise only observed in grazing cattle the lower cscontent in meat of cattle housed during the summer season is due to the more varied fodder which is at that time less contaminated than green crop during the winter season november to march the highest contaminations in the meat of confined bohemian forest or grazing cattle alps was measured when the animals in these districts were almost exclusively fed with fodder from the own farmground or with leafy silage the highest contamination was almost regularly noticed in january february and march as generally during these months the highly contaminated first cut hay is fed here the meat was often even more contaminated than that of grazing cattle after the quick decrease of cs in fallout noticed in the years and in a dependance in the cscontamination of beef on the methods of keeping and feeding could still be observed in only the extreme cases alps bavarian and bohemian forest though in general meat of animals from districts with heavy rainfall was slightly more contaminated than meat of animals from regions with less precipitation

95

feeding

both udpglucuronyltransferase gt and betaglucuronidase betag were assayed in untreated liver microsomes optimum assay conditions were established with rat CL microsomes using pnitrophenol pnp and its glucuronide pnpga at the ph optima of gt and betag the MICs of the two enzymes were compared using microsomes from rats mice pigs cattle and horses with pnp pnpga and phenolphthalein as ATP in the presence of various cofactors and inhibitors at ph and these data disclose pronounced differences with respect to species substrate and other experimental conditions thereby precluding the establishment of general optimum conditions the two enzymes were also assayed under strictly MZ conditions using pnp and pnpga and rat liver microsomes at ph in the presence and absence of udpglucuronate disodium udpga activators atpudpnacetylglucosamine and inhibitors when provided with a PET level of udpga both enzymes proved active under those conditions and a conjugationdeconjugation interplay was indicated the two processes could be selectively and totally inhibited by zn and saccharolactone the results suggest that conjugationdeconjugationreconjugation cycles may be operative in the metabolism of drugs in vivo taking place already at the level of the CL endoplasmic reticulum

19|37|59|101|130|184

liver|activities|substrate|identical|functional|liver

SS CL and renal gammaglutamyl transpeptidase ggt activities were studied in four groups of rabbits controls rabbits with obstructive extrahepatic cholestasis rabbits with obstructive anuria and animals with combined obstructive extrahepatic cholestasis and obstructive anuria SS ggt was essentially increased in rabbits with obstructive extrahepatic cholestasis showing peak values in the combined cholestasis obstructive anuria group and practically normal values in animals with anuria liver ggt was increased in both cholestasis groups but the increase was less prominent than the increase in serum ggt and there was no correlation between them in both anuric groups renal ggt was reduced probably as a result of inhibited enzyme synthesis secondary to the altered conditions for adequate renal function the results obtained are suggestive of a probable renal involvement in the formation of the SS ggt activity level

0|1|35|131

serum|liver|serum|serum