bluuebunny/crossref_metadata_2025 huggingface dataset:
ADENYLATE AND 2,6-DIAMINOPURINE RIBONUCLEOTIDE PYROPHOSPHORYLASE ACTIVITIES OF L CELLS
Authors: Blair D. G. R.
Published: December 2009

The reaction kinetics of adenylate (AMP) and 2,6-diaminopurine ribonucleoside 5′-monophosphate (DAPRP) pyrophosphorylase activities of extracts of L-strain mouse fibroblast cells were studied by chromatographic and radioactive tracer techniques. The apparent Kmvalues found for 5-phosphoribosyl-α-1-pyrophosphate (PRPP) were 6.9 × 10−5 M for AMP pyrophosphorylase activity and 3.6 × 10−4 M for DAPRP pyrophosphorylase activity. The apparent Kmfound for adenine was 3.0 × 10−5 M, whereas the apparent Kmcalculated for 2,6-diaminopurine was 1.8 × 10−3 M. An optimum pH of 7.6 was found for AMP pyrophosphorylase, whereas an optimum pH range of 7.6–7.9 was found for DAPRP pyrophosphorylase activity. Under assay conditions of zero-order kinetics, the AMP pyrophosphorylase activities of L-cell extracts were approximately twice the DAPRP pyrophosphorylase activities of the same extracts.AMP and DAPRP were found to be the major products of the AMP and DAPRP pyrophosphorylase reactions, respectively. DAPRP was analyzed chemically and spectrophotometrically, and absorption spectra at different pH values are presented.The effects of sulfate ions, storage, and enzyme inactivation techniques on enzyme activities were also studied.
LIPOVITELLIN, PHOSVITIN AND OTHER GRANULE COMPONENTS IN AVIAN YOLK DURING EMBRYOGENESIS
Authors: Martin W. G. , Saito Z.
Published: December 2009

Fertile avian eggs were incubated for 0, 6, 15, and 18 days and the phosvitin–lipovitellin fraction (PvLv) was isolated from the yolk granules. PvLv was chromatographed on TEAE-cellulose and peaks were eluted at the usual positions of β- and α-lipovitellins and residual PvLv complexes for each incubation period. The proportion (relative to the PvLv applied) of β-lipovitellin was fairly constant but its protein phosphorus content decreased, whereas α-lipovitellin decreased in relative proportion but not in protein phosphorus content which remained constant with increasing incubation time. Two new granule components, appearing after 15 days of incubation and demonstrated by ultracentrifugation and electrophoresis, were not resolved from the known components on TEAE-cellulose. Both were isolated by gel nitration and one was found to be ovalbumin that could be removed by thorough washing of the granules. The other was a phosphopeptide (0.7% P) having solubility properties similar to lipovitellin and a molecular weight of about 9000. Material insoluble in 10% NaCl accumulated in the granule fraction and amounted to nearly 40% of this fraction after 18 days of incubation.
FREE SULFHYDRYL GROUPS IN HAPTOGLOBIN
Authors: Tattrie Brenda L. , Connell G. E.
Published: December 2009

Human haptoglobin of types 1-1 and 2-2 has been examined for its content of free sulfhydryl groups by two methods: (i) treatment of haptoglobin in the presence of 7.2 M guanidine hydrochloride with 14C-iodoacetate followed by acid hydrolysis and determination of 14C-carboxymethylcysteine content, and (ii) spectrophotometric titration of haptoglobin in the presence of 7.2 M guanidine hydrochloride with p-chloromercuribenzoate. By both methods, the content of free sulfhydryl was less than 1 equiv/105 g of protein.
STUDIES ON THE CONFORMATIONAL CHANGES OF MITOCHONDRIAL MALATE DEHYDROGENASE IN UREA–PHOSPHATE SOLUTIONS
Authors: Seguin R. J. , Kosicki G. W.
Published: December 2009

Pig-heart mitochondrial malate dehydrogenase is gradually inactivated in 4 M urea. During the inactivation, sulfhydryl groups on the protein are exposed in a first-order reaction. The reaction is followed spectrophotometricaily using the sulfhydryl reagent, 5,5′-dithiobis(2-nitrobenzoate) (DTNB). Titration with DTNB in the presence of urea exposes 10 to 12 sulfhydryl groups per molecule of mitochondrial malate dehydrogenase. The enzyme is also inactivated when diluted in water but no sulfhydryl groups are unmasked. The loss of activity and the appearance of sulfhydryl groups in urea solutions do not take place at the same rate.The conformational changes of malate dehydrogenase that occur in urea solutions are partially prevented by inorganic phosphate ions, and less so by the substrates NADH, NAD+, oxalacetate (OAA), and L-malate. The protection against loss of enzyme activity by inorganic phosphate ions is pH-dependent. Both inorganic phosphate and NADH considerably reduce the first-order rate constant for sulfhydryl appearance in 4 M urea. Protection of the enzyme against sulfhydryl appearance in urea solutions by pre-incubation with the substrates indicates that about two sulfhydryl groups per molecule of mitochondrial malate dehydrogenase are involved in substrate binding. Thus, the substrates must keep the active site of the enzyme intact. They either bind to the sulfhydryl groups or prevent the protein molecule from completely unfolding.
EXPERIMENTAL ALKAPTONURIA IN THE RAT INDUCED BY TRYPTOPHAN DEFICIENCY
Authors: Woodford V. R. , Quan Lillian , Cutts F.
Published: December 2009

An experimental alkaptonuria induced by tryptophan deficiency has been observed in the rat. The condition of alkaptonuria followed development of signs of tryptophan deficiency as judged by weight loss of the young, growing rat and its general appearance. Homogentisic acid was identified by a comparison of its behavior on thin-layer chromatography with authentic homogentisate and by means of the enzyme homogentisic acid oxidase. The condition was relieved by the return of tryptophan to the diet.
A MATHEMATICAL ANALYSIS OF THE COMBINED TRICARBOXYLIC ACID - GLYOXYLATE CYCLES
Authors: Branion R. M. R. , Caddick B. F. J. , McConnell W. B.
Published: December 2009

The problem of interpreting data on the distribution of isotopic carbon in intermediates of the tricarboxylic acid cycle and the glyoxylate cycle is discussed. An effort is made to examine mathematically the effects of cycling on the distribution of isotope in the carbon skeletons of intermediates of these cycles. Consideration is given to the individual cycles and to combinations of the two. Because the systems are highly complex, a number of simplifying assumptions are made which limit the usefulness of the equations derived for dealing with experimental data. However, some significant features of labelling that result from combined operation of the two cycles are emphasized, which should make it possible to estimate their relative contributions more reliably than by qualitative inspection of the data.
PURIFICATION AND PROPERTIES OF FRUCTOSE DIPHOSPHATE ALDOLASE FROM FUSARIUM OXYSPORUMF. LYCOPERSICI
Authors: Ingram J. M. , Hochster R. M.
Published: December 2009

Fructose-1,6-diphosphate (FDP) aldolase obtained from crude extracts of the mycelium of Fusarium lycopersici was purified approximately 35-fold. The properties of the enzyme indicate that it resembles the FDP aldolase commonly found in yeast and bacteria rather than that found in animals or plants. The inhibitory action of p-hydroxymercuribenzoate, N-ethylmaleimide, and iodosobenzoate suggests that a sulfhydryl group may be involved in an active site. The inhibitions caused by methylene blue in the presence of light and of diazosulfanilic acid suggest that histidine and (or) tyrosine residues may also be involved in the active site. The importance of this site has been established by demonstrating that fructose diphosphate and D-glyceraldehyde-3-phosphate prevent inactivation by diazosulfanilic acid whereas dihydroxyacetone phosphate is without effect.
FACTORS INFLUENCING THE NUTRITIONAL VALUE OF FISH FLOUR: V. CHLOROCHOLINE CHLORIDE, A TOXIC MATERIAL IN SAMPLES EXTRACTED WITH 1,2-DICHLOROETHANE
Authors: Munro I. C. , Morrison A. B.
Published: December 2009

Extraction of lyophilized cod fillets with 1,2-dichloroethane resulted in the formation of chlorocholine chloride (CCC) ((2-chloroethyl)trimethylammonium chloride), a toxic choline derivative. CCC isolated chromatographically from 1,2-dichloroethane-extracted fish was identical with CCC prepared by reacting 1,2-dichloroethane with trimethylamine. The infrared spectrum of the reineckate salt of CCC isolated from 1,2-dichloroethane-extracted fish also was found to be identical with synthetic chlorocholine reineckate. A method for the determination of CCC in 1,2-dichloroethane-extracted fish is described.
REDUCED NICOTINAMIDE–ADENINE DINUCLEOTIDE OXIDATION IN ESCHERICHIA COLI PARTICLES: III. CELLULAR LOCATION OF MENADIONE REDUCTASE AND ATPase ACTIVITIES
Authors: Bragg P. D. , Hou Cynthia
Published: December 2009

Sonic extracts of Escherichia coli were fractionated to membrane-wall, small-particle, and soluble fractions. Menadione reductase and ATPase activities were found in all fractions. The menadione reductase activity of the soluble fraction was resolved into three enzymes. Enzymes with properties similar to two of these could be released from the particulate fraction by treatment with sodium dodecyl sulfate or chelating agents. The major ATPase of the particulate fractions was solubilized by detergent. Osmotic shock experiments suggested that it was located outside the plasma membrane in the intact cell. It differed from the ATPase of the soluble fraction. An enzyme resembling the latter ATPase was solubilized from the small-particle fraction by chelating agents and could be rebound in the presence of magnesium ions. Solubilized menadione reductase was not rebound to particulate fractions under these conditions.
EFFECTS OF HEPARIN IN VIVO ON LYSOSOMAL ENZYMES IN RAT PLASMA
Authors: Levy S. W.
Published: December 2009

Studies were carried out to determine the effects of heparin in vivo on acid ribonuclease, β-glucuronidase, acid β-glycerophosphatase, cathepsin, and several esterases in rat plasma. Increases occurred regularly in the specific activities of ribonuclease and β-glucuronidase, and inconsistently in that of acid β-glycerophosphatase. The activity of β-glucuronidase increased to a smaller extent in control animals. No change was observed in the activities of cathepsin or benzoylarginine ethyl esterase. Tributyrin esterase activity increased following the injection of heparin, the rise in total activity being due to an increase in the activities of both eserine-resistant and eserine-sensitive esterases in rat plasma. The results were discussed in terms of possible mechanisms of action of heparin and the significance of lysosomal enzymes in blood.
ISOLATION, PURIFICATION, AND CHARACTERIZATION OF γ-LIPOTROPIC HORMONE FROM SHEEP PITUITARY GLANDS
Authors: Chrétien M. , Li Choh Hao
Published: December 2009

The isolation and characterization of a new biologically active polypeptide from sheep pituitary glands is described. Considerable evidence suggests that the structure of the new molecule, designated γ-lipotropin, is identical with the N-terminal portion (sequence 1–58) of β-lipotropin and, therefore, that γ-lipotropin contains at its C-terminus the amino acid sequence of β-melanophore-stirnulating hormone (β-MSH). The implications of these results are discussed in relation to the mechanism of pituitary peptide biosynthesis and to the structure–activity relationships between sheep β-MSH and lipotropic hormones.
THE METABOLISM OF MUCOPOLYSACCHARIDES: III. THE EFFECT OF ADRENOCORTICAL HORMONES ON ENZYMES INVOLVED IN GLUCURONIDE SYNTHESIS AND METABOLISM IN CONNECTIVE TISSUE
Authors: Foster T. S.
Published: December 2009

The levels of activity of hexokinase, phosphoglucomutase, uridine diphosphoglucose pyrophosphorylase, and uridine diphosphoglucose dehydrogenase, which are involved in the synthesis of glucuronic acid, and the levels of glucuronosyltransferase and β-glucuronidase, which are involved in its metabolism, were studied in connective tissue from polyvinyl sponge implants from sham-operated and adrenalectomized rats which had received "replacement therapy" of individual steroids.The levels of activity of these enzymes were significantly increased in sham-operated rats which had been treated with corticosterone, cortisone, or hydrocortisone. In adrenalectomized animals, the increased or decreased enzyme activities were restored to normal levels by "therapy" with corticosterone, cortisone, or hydrocortisone. In some cases there was an over-correction at the particular level of hormone treatment. In both sham-operated and adrenalectomized animals, treatment with deoxycorticosterone, progesterone, or Reichstein's substance S frequently, but not always, resulted in little or no change in activity of the enzymes.
THE DIFFERENTIAL DETERMINATION OF CONJUGATED HYDROXYSKATOLES IN HUMAN URINE
Authors: Mahon M. E. , Mattok G. L.
Published: December 2009

A method is described for the separation and estimation of 4-, 5-, 6-, and 7-hydroxyskatole sulfate esters in urine. After extraction from urine, the 5-, 6-, and 7-hydroxyskatole sulfate esters were hydrolyzed by a sulfatase preparation to the corresponding hydroxyskatoles. The 4-isomer was resistant to this enzymic hydrolysis. The hydroxyskatoles were then extracted by ethyl acetate from the hydrolyzate followed by extraction of the 4-sulfate ester by n-butanol. Each fraction was chromatographed on silica gel G thin layers, sprayed with a modified Ehrlich's reagent (p-N,N-bis(2-chloroethyl)aminobenzaldehyde), and the appropriate zones eluted from the chromatogram. The concentrations of each isomer originally present in the urine were estimated from the absorbances of the four eluates at their absorption maxima (ca. 600 mμ). The levels of the four isomeric skatolyl sulfates found in urines from 10 normal controls are given.
THE PHYSICOCHEMICAL PROPERTIES OF HUMAN HEMAGGLUTININS TO TUBERCULIN PURIFIED PROTEIN DERIVATIVE
Authors: Turcotte Raymond , Freedman Samuel O. , Sehon Alec H.
Published: December 2009

Two distinct types of hemagglutinins to the tuberculin purified protein derivative (PPD) can be detected in human sera by the bisdiazotized benzidine (BDB) passive hemagglutination technique. The sera of patients with active pulmonary tuberculosis contained two types of hemagglutinins with properties of IgG- and IgM-immunoglobulins, the former being in excess. On the other hand, most of the hemagglutinins produced by healthy individuals with positive tuberculin skin reactions had physicochemical properties similar to those of IgM- and (or) IgA-globulins.
INHIBITION OF EUGLENA MACROMOLECULE SYNTHESIS BY N-METHYL-N′-NITRO-N-NITROSOGUANIDINE AND N-METHYL-N-NITROSO-p-TOLUENESULFONAMIDE
Authors: Allan Robert K. , McCalla D. R.
Published: December 2009

Concentrations of N-methyl-N′-nitro-N-nitrosoguanidine and N-methyl-N-nitroso-p-toluenesulfonamide, which temporarily inhibit the growth of Euglena gracilis Z, inhibit the synthesis of DNA, RNA, and protein. Nucleic acid synthesis (both RNA and DNA) is inhibited immediately, and protein synthesis becomes inhibited after 45–60 min.
CONVERSION OF A DIETARY TRIGLYCERIDE INTO DEPOT FAT IN FISH AND LOBSTER
Authors: Brockerhoff H. , Hoyle R. J.
Published: December 2009

Cod, trout, and lobsters were fed a triglyceride that contained oleic-9,10-8H acid in the β and oleic-1-I4C acid in the α positions. The distribution of the labels in the α and β positions of the depot fat was then analyzed. The original distribution had been retained to a large extent in the lobster, indicating a retention of the β-monoglyceride structure of the dietary fat in this invertebrate. In the fish, there was an apparent partial retention of8H in the β position, but the14C of the originally α-bound acids was now almost randomly distributed. These results may be interpreted as supporting the hypothesis that the β-monoglyceride structure of dietary fat is partly retained by fish. It is clear, however, that in fish, though not in lobster, the larger part of the fat had been broken down completely before deposition.
VARIATION OF THE ENZYMES OF THE UREA CYCLE AND ASPARTATE TRANSCARBAMYLASE IN LIVER OF PREGNANT RATS
Authors: Roberge A. , Charbonneau R. , Berlinguet L.
Published: December 2009

The variations in the specific activities of the enzymes of the urea cycle were studied in the livers of pregnant rats and also in the livers of male rats and other females with the same body weight. The specific activities of the five enzymes of the urea cycle are the same in male and in female except for argininosuccinase. The activity of this enzyme is twice as high in female rats as in male rats. In pregnancy, the activities of the enzymes of the urea cycle are decreased except for arginase, which increases. Aspartate transcarbamylase remains constant during the same period.These results lead to the supposition that another pathway for the synthesis of orotic acid may exist, or more probably that there exist two carbamyl phosphate synthetases, one for pyrimidine biosynthesis and one for urea synthesis.
POSTNATAL CHANGES OF ACTIVITY AND ELECTROPHORETIC PATTERN OF JEJUNAL AND ILEAL NONSPECIFIC ESTERASE AND ALKALINE PHOSPHATASE OF THE RAT: EFFECT OF ADRENALECTOMY
Authors: Pelichová H. , Koldovský O. , Heringová A. , Jirsová V. , Kraml J.
Published: December 2009

During postnatal development of the rat, the activity of nonspecific esterase (substrate, β-naphthyl acetate) in the jejunum and ileum increased. Electrophoresis showed that distribution of this enzyme was different in these two parts of the intestine in the suckling rat, whereas the zymogram was the same for both parts in the adult rat. In intact animals, the degree of inhibition of nonspecific esterase activity by 10−4 M eserin, 5 × 10−8 M di-ethyl p-nitrophenyl phosphate (E.600), and 0.4 M NaCl was different, but there were no differences with any one inhibitor between the jejunum and the ileum of suckling and weanling rats. Adrenalectomy at 7 days of age did not influence the activity of the enzyme, but at 14 days of age it inhibited the rise of activity in jejunum and ileum. Adrenalectomy influenced the sensitivity of nonspecific esterase activity to inhibition by eserin and E.600. When cortisone was administered to adrenalectomized rats, certain characteristics of the enzyme (specific activity, sensitivity to various inhibitors, zymogram) were, in most case, comparable with those of preparations from normal controls.During postnatal development, the activity of alkaline phosphatase (substrate, β-naphthyl phosphate) in the jejunum showed practically no change, but in the ileum it decreased. Change in the zymogram was of the same type in both jejunum and ileum. Adrenalectomy at 7 days of age was followed by a fall in activity in the ileum that was apparent at 14 days of age, but the zymogram was not affected. Adrenalectomy on day 14 did not produce an apparent change by day 21, but there was retention of the earlier electrophoretic pattern. When cortisone was administered to adrenalectomized rats, certain characteristics of the enzyme (specific activity, zymogram) were comparable with those of preparations from normal controls.The results are discussed from the point of view of difference between the jejunum and ileum of suckling animals, and the influence of the adrenal glands.
THE ACTIVATION OF CHYMOTRYPSINOGEN B: I. FACTORS AFFECTING THE GENERATION OF CHYMOTRYPTIC ACTIVITY
Authors: Parkes C. Owen , Smillie L. B.
Published: December 2009

The bovine pancreatic zymogen, chymotrypsinogen B, can be activated by trypsin to form chymotrypsin B. The rate of activation, maximum enzymic activity, and the stability of this activity were found to be influenced by such factors as pH, temperature, trypsin concentration, Ca++ ions, and inhibitors. The results are discussed and compared with the events known to occur during chymotrypsinogen A activation. Although chymotrypsinogen B is activated more rapidly than chymotrypsinogen A, the resulting esterase activity is lower. There is evidence to suggest that, besides the initial break in the polypeptide chain catalyzed by trypsin, further autolytic cleavages take place which result in forms of chymotrypsin B with reduced esterase activity.
SOME METABOLIC CHANGES RESULTING FROM TREATING KIDNEY TISSUE WITH TRYPSIN
Authors: Phillips Hugh J.
Published: December 2009

Trypsin increased the oxygen uptake of cell suspensions or slices from rat kidney. An increased oxygen uptake with trypsin did not occur in the presence of soybean trypsin inhibitor. Ethylenediaminetetraacetate, which will free cells from tissue, did not change the oxygen uptake, and cell suspensions prepared by trypsinization took up oxygen at a greater rate than cell suspensions prepared mechanically. Chymotrypsin also enhanced respiration. In addition to oxygen uptake, other metabolic processes were changed when trypsin was added to tissue. There was a loss of cellular lactate dehydrogenase, and lactate formation decreased. Slight amounts of pyruvate accumulated in reaction vessels when cell suspensions respired, but this was less in those treated with trypsin. Both intra- and extra-cellular amino and keto acids were increased by trypsin. The increased oxygen uptake with trypsin was only partially blocked by cyanide.
PHOSPHONOLIPIDS: XIV. DETECTION AND IDENTIFICATION OF GLYCEROLPHOSPHONOLIPIDS IN THE PRESENCE OF THEIR PHOSPHOLIPID ANALOGUES BY PAPER CHROMATOGRAPHY OF THEIR SAPONIFICATION PRODUCTS
Authors: Baer Erich , Sarma G. Raghupati , Robinson Ranga , Sastry P. S.
Published: December 2009

A procedure for the detection and identification of α-glycerolphosphonolipids in the presence of their phosphoric acid analogues, viz. α-lecithins and α-cephalins, is described. It combines the saponification of these compounds by a modified Dawson procedure with the separation and identification of the saponification products by descending paper chromatography with n-butanol, glacial acetic acid, and water (5:3:1, v/v/v), and staining of the chromatograms with ninhydrin and molybdate sprays.The relative mobilities of the saponification products, viz, α-glycerol-(2-trimethylammoniumethyl)phosphonate, α-glyceryl-(2-aminoethyl)phosphonate, α-glycerolphosphorylcholine, and α-glycerylphosphorylethanolamine with respect to each other and to α-glycerophosphoric acid have been determined.
METABOLISM OF AMINO ACIDS IN AGROBAGTERIUM TUMEFACIENS: III. UPTAKE OFL-PROLINE
Authors: Behki R. M.
Published: December 2009

The characteristics of14C-proline uptake by cells of Agrobacterium tumefaciens are described. The results obtained were different from those reported for other bacteria (e.g. Escherichia coli). In addition, significant differences were observed with cells of the non-tumorogenic strain, IIBNV6, as compared to the tumorogenic strain, IIBV7K.Uptake of14C-proline by both strains of cells did not show the specificity known to exist for this amino acid in other microorganisms. A host of unrelated amino acids inhibited proline uptake. Moreover, the inhibitory effects of some amino acids were different in the two strains. Although glutamate and cysteine had no effect on14C-proline uptake in IIBNV6cells, they showed strong inhibition in IIBV7K cells. In addition, cells of the latter strain metabolized proline to a much greater extent than IIBNV6cells.In growing IIBV7K cells, glycine and glutamate suppressed14C-proline uptake and its incorporation into protein. They were also able to displace accumulated14C-proline from the cells. Glycine and leucine, which inhibited proline uptake in IIBNV6cells, showed a similar effect on the displacement of accumulated14C-proline in these cells.Hydroxylamine and Δ′-pyrroline carboxylate suppressed14C-proline uptake and its incorporation into protein in IIBNV6ceils. In IIBV7K cells, on the other hand, Δ′-pyrroline carboxylate had no effect on14C-proline uptake. The incorporation of the label into protein was only slightly reduced. Hydroxylamine in these cells showed a lesser degree of uptake inhibition but a stronger suppression of label incorporation into protein.
PROCEDURE FOR DETERMINATION OF ALDOSTERONE IN HUMAN PERIPHERAL PLASMA BY DOUBLE-ISOTOPE DERIVATIVE ASSAY, AND ITS APPLICATION FOR MEASUREMENT OF SECRETORY RATE AND URINARY EXCRETION
Authors: Nowaczynski Wojciech , Silah Jack , Genest Jacques
Published: December 2009

This is a report of a procedure for the determination of peripheral plasma aldosterone, in which14C-labeled aldosterone serves as the marker, and the acetylating agent is relatively inexpensive tritium-labeled acetic anhydride of high specific activity. A new method for the chromatographic purification of aldosterone and aldosterone diacetate is presented. This procedure provides a better separation of these two compounds from the unlabeled and labeled impurities.
EFFECT OF X-RADIATION ON THE TRYPTIC DIGESTION OF ALBUMIN AND ERYTHROCYTE MEMBRANE PROTEINS
Authors: Myers D. K. , Bide R. W. , Tribe T. A.
Published: December 2009

Bovine serum albumin was more susceptible to tryptic digestion after X-irradiation. This was probably because of an increase in the number of peptide bonds readily available for enzymic hydrolysis. However, the irradiated albumin did not show any marked change in its physical properties. The effect of X-radiation on the albumin was attributed, at least in part, to the radiation-induced cleavage of a small fraction of the S—S bonds in the albumin molecule.Similar effects were noted after irradiation of intact erythrocytes. Low concentrations of trypsin, chymotrypsin, or papain removed the protein on the exterior surface of the cell membrane much more rapidly from irradiated (60 krads) than from control cells, thus resulting in a high degree of sensitization to snake venom phospholipases.
CELL-FREE INCORPORATION OF AMINO ACIDS BY A TROUT-LIVER SYSTEM. HEAT-LABILE AMINOACYL TRANSFERASE ACTIVITY
Authors: Rosen Lawrence , Murray E. L. , Novelli G. David
Published: December 2009

A cell-free system from trout liver that incorporates amino acids into protein has been isolated. The system requires both soluble and particulate fractions, and is similar to those isolated from other organisms.The incorporation of amino acids is extremely heat-labile, and this lability has been localized in the aminoacyl transferase activity of the cell sap. The heat lability of the microsomes may also be related to transferase activity.Ribosomal fractions from trout liver and rat liver incorporate amino acids when incubated with cell sap from rat liver and trout liver, respectively.
Polynucleotidase activity of animal and plant tissue phosphodiesterases
Authors: Razzell W. E.
Published: December 2009

The purification of phosphodiesterase I from hog liver has permitted the demonstration that its properties and catalytic activity are the same as the enzyme previously purified from kidney. The liver, kidney, and snake venom phosphodiesterase I preparations have been compared on the basis of their ability to hydrolyze p-nitrophenyl esters of the 5′-phosphates of thymidine, uridine, and deoxyadenosine at pH 9 in the absence of EDTA versus the activity of potato nucleotide pyrophosphatase, which is active at pH 7 in the presence of EDTA. Kidney microsomes are similarly inactive at the lower pH. Further, the tissue and venom enzymes possess activity against pTpT, TpT, and ribooligonucleotides which are not attacked by the plant nucleotide pyrophosphatase.A comparison of the loss of activity during heating, rates of hydrolysis, kinetics, and competitive inhibition of the animal tissue phosphodiesterase I on several substrates indicates that one catalytic site is responsible for the cleavage of nucleoside 5′-phosphate from p-nitrophenyl esters, TppT, and NAD+. The tissue enzyme, like the venom enzyme, is active on the 3′-hydroxyl terminus of transfer RNA.
Ribosome aggregates of the midgut of silkworm, Bombyx mori L.
Authors: Hayashi Y.
Published: December 2009

Ribosomal pellets were isolated from midgut cells of fifth-instar larvae of Bombyx mori, and sedimentation patterns of fractions obtained by sucrose-gradient centrifugation were examined before and after treatment with RNase and trypsin. The control preparation contained free monoribosomes and ribosomal assemblages. RNase released di- and tri-ribosomes, trypsin released mono-, di-, and tri-ribosomes, and both together released monoribosomes. The results suggest that the ribosomal assemblage may be stabilized by protein or peptide synthesized on the ribosomes.
Differences in lactate dehydrogenase isoenzyme patterns in experimental lesions of the stomach
Authors: Procházka B. , Kohout J. , Korbová L. , Jirásek V. , Bárta V. , Procházková M.
Published: December 2009

Changes in the LDH isoenzyme patterns and in the total LDH activity in fundic and pyloric mucosa and muscular layers provoked by restraint ulcers in rats were investigated. The changes in the proportions of the individual LDH isoenzymes were considered as indicators of the energy-production ratio produced by anaerobic glycolysis and by aerobic oxidative cycles.In rats with experimental gastric lesions, the LDH isoenzyme patterns in the fundic mucosa adjacent to the lesions and in the pyloric mucosa showed an increase of LDH 5 and a decrease of LDH 1 (a move toward higher proportions of monomer M in the H:M ratio). In the mucosa of the remaining part of the fundic area, different changes in the LDH isoenzyme pattern were observed.The LDH isoenzyme pattern in the muscular layer of both gastric areas was not influenced by experimental gastric lesions.In the discussion, an explanation for the changes in the LDH isoenzyme patterns is attempted.
The metabolism of isolated pneumocytes from rabbit lung
Authors: Wolfe B. M. J. , Rubinstein D. , Beck J. C.
Published: December 2009

Isolated pneumocytes from peripheral rabbit lung were prepared with the aid of collagenase. This preparation contains about 40% alveolar cells, the remainder being either small round cells (35%) or unidentified. This preparation can potentially serve for the isolation of homogenous populations of cells. The pneumocytes oxidize glucose-1-14C and glucose-6-14C to 14CO2 with C1: C6 ratio of 7. Succinate-2,3-14Coxidation to 14CO2 is inhibited by malonate. The pneumocytes also incorporate palmitate-9, 10-3H into phospholipids, lecithin having the highest specific activity. The rate of these metabolic activities was comparable to that in slices.
Some properties of cytoplasmic RNA fractions of the mouse Ehrlich ascites carcinoma
Authors: Hosokawa K. , Fraser M. J.
Published: December 2009

Two RNA subfractions from mouse Ehrlich ascites carcinoma 105 000 × g supernatant and three RNA subfractions from the tumor microsomal fraction have been resolved by chromatography on methylated albumin–kieselguhr. The five subfractions have been examined for their amino acid acceptor capacities and nucleotide compositions and by sucrose density-gradient centrifugation. One of the 105 000 × g supernatant fractions has been identified as amino acid acceptor or transfer RNA (tRNA) and the three microsomal components have been identified as tRNA, 5S RNA, and ribosomal RNA. The microsomal tRNA and 5S RNA appear to be associated with ribosomal RNA in a molar ratio approaching 2:1 and together make up about 6–8% of the total microsomal RNA. The second 105 000 × g supernatant RNA fraction has not been identified. It is recovered in widely varying amounts and behaves like heterogeneous material in chromatographic and sedimentation procedures.
Agents affecting lipid metabolism. XXXIII. A mitochondrial swelling technique for the preparation of a liver extract which suppresses cholesterogenesis in vitro
Authors: Cayen M. N.
Published: December 2009

The presence in liver mitochondria of starved rats and rabbits of a factor which suppresses cholesterogenesis in rat liver homogenates was reported in a previous communication. Attempts were made to prepare a less complex mixture by modifying the isolation procedure. It was found that suspension of the mitochondria in water, prior to centrifugation and sonification, resulted in a preparation which was three times more active in suppressing cholesterogenesis in vitro than the preparation isolated by previously reported techniques. In addition to the premevalonate site of action, a smaller but pronounced inhibition was also observed after the formation of mevalonic acid.
Studies on γA-globulins and α2-macroglobulins. Characterization of γA- and α2-macroglobulins
Authors: Sanders Benjamin E. , Oh Yang H.
Published: December 2009

Fractionation into several individual components was achieved from Cohn's Fraction III of human plasma by the successive application of separation principles that depend on solubility, charge, and size (precipitation, ion-exchange chromatography, and molecular-sieve chromatography methods). Characterization was made by various electrophoretic procedures such as microzone on cellulose acetate, disc on acrylamide gel, and immunoelectrophoresis, and includes some physicochemical properties of the purified proteins. There are found to be various components of γ-globulins, α2-macroglobulins, β-glycoproteins, β-lipoproteins, and other minor proteins in Cohn's Fraction III of normal human plasma. The physicochemical properties of two γA-globulins and two α2-macroglobulins were investigated.
The use of bacteriophage neutralization technique for the detection of anti-hapten antibody
Authors: Carter B. G. , Yo S. L. , Sehon A. H.
Published: December 2009

The phage neutralization technique has been exploited for the detection of rabbit antibodies against the 2,4-dinitrophenyl residue. The sodium salt of dinitrobenzene sulfonate was allowed to react with bacteriophage T2 and the surviving hapten-bacteriophage conjugates (HBC) were found to be inactivated by the anti-hapten antiserum. Amounts of antibody as low as 2 × 10−3 μg were detected by this technique. The specificity of the reaction was demonstrated by the inhibition with structurally related haptens of the neutralization of HBC by anti-hapten antibody.
The stimulation by phosphate and the inhibition by adenine nucleotides and nicotinamide–adenine dinucleotide of the respiratory chain
Authors: Blanchaer M. C
Published: December 2009

Steady-state kinetic experiments with pigeon heart mitochondria and electron-transport particles (ETPH), with NADH as substrate in the absence of phosphate and with coenzyme Q1 or ferricyanide as the electron acceptor showed that ADP and ATP are competitive inhibitors at the NADH dehydrogenase level of the respiratory chain. The ADP effect was hyperbolic competitive in type indicating that this nucleotide inhibits by decreasing the affinity of the dehydrogenase for NADH rather than by competing for the NADH binding site of the enzyme. The inhibition by ADP and ATP does not involve energy-conserving reactions since it is not relieved by oligomycin or Dicoumarol. NAD+ also is an inhibitor of the NADH dehydrogenase of ETPH but is noncompetitive with respect to NADH. Phosphate stimulates NADH oxidation by ETPH and mitochondria in the absence of ADP when O2 is the electron acceptor. Since this effect is absent when CoQ1 or ferricyanide replaces O2 as the acceptor, it would appear that phosphate stimulates the respiratory chain on the O2 side of ubiquinone during noncoupled respiration.
β-Glucuronidase of rat-liver lysosomes: pH–activity curves
Authors: Delvin E. , Gianetto R.
Published: December 2009

A partially purified extract was obtained of a rat-liver fraction containing the mitochondria and lysosomes. Two components with β-glucuronidase activity were separated from it. Both showed the same pH optima at 4.7 and 5.35. The pH–activity curves were different with different ionic strengths of the buffer.
A simple method for the isolation of fraction I protein of chloroplasts
Authors: Wilson J. H. , McCalla D. R.
Published: December 2009

Application of the standard methods for the preparation of fraction I protein (ribulosediphosphate carboxylase) from spinach leaves gives low yields when applied to other species. We describe here simple methods for the preparation of pure fraction I protein in good yield from spinach, peas, beans, and Chlorella. The electrophoretic mobilities (on polyacrylamide electrophoretograms) of bean and Chlorella fraction I differ from each other and from the mobilities of pea and spinach protein.
β-N-Acetylglucosaminase in bovine milk
Authors: Mellors A.
Published: December 2009

A β-N-acetylglucosaminase has been found in bovine milk, and its properties have been investigated. The highest specific activity of the enzyme was found to be associated with cellular material that can be readily sedimented. The enzyme resembles catalase in its distribution within the subfractions of milk, and may be derived from milk leucocytes. The optimum pH for the hydrolysis of p-nitrophenyl β-N-acetylglucosaminide is 4.2 and the apparent Michaelis constant for this hydrolysis is 1.0 mM. The enzyme is inhibited by acetate ions, N-acetylglucosamine, and heparin. Inhibition by p-chloromercuribenzoate is not overcome by excess dithiothreitol.
The reduction of SU-4885 by adrenal glands and other tissues and its inhibition by ACTH
Authors: Kraulis I. , Traikov H. , Li M. P. , Lantos C. P. , Birmingham M. K.
Published: December 2009

Rat adrenal glands convert 2-methyl-1,2-bis(3-pyridyl)-1-propanone (SU-4885) in vitro to a product with physical and chemical properties indicating the reduction to 2-methyl-1,2-bis(3-pyridyl)-1-propanol. The same compound is also formed by the reduction of SU-4885 with NaBH4. The reduction of SU-4885 also occurs in the presence of frog adrenal, rat kidney, and most actively, rat liver tissue, and depends on the concentration of SU-4885 in the incubation medium. Added deoxycorticosterone, at the concentration used, had no effect, but ACTH inhibited the reduction by both adrenal and liver tissue.
Studies on the nature of the seromucoid and haptoglobin responses to experimental inflammation
Authors: Maung M. , Baker D. G. , Murray R. K.
Published: December 2009

The effects of the administration of actinomycin D, ethionine, and puromycin on the elevations of the total seromucoid fraction and of one of its components (haptoglobin) occurring during experimental inflammation have been studied. All three inhibitors of protein synthesis abolished the elevation of haptoglobin level. Ethionine and puromycin also completely suppressed the elevation of total seromucoid level, whereas actinomycin D only partially suppressed it. The seromucoid and haptoglobin levels in control animals injected with only the inhibitors of protein synthesis were not in general significantly different from those of the animals injected with turpentine and these agents. The results are consistent with the concept that the elevation of various plasma glycoproteins occurring during inflammation is principally due to de novo synthesis of these proteins rather than release of preformed proteins from tissue pools.
Properties of turpentine relative to the effects on fowl plasma in vitro. II. The separation of peroxide components of turpentine by thin-layer chromatography
Authors: Darcel C. le Q.
Published: December 2009

Thin-layer chromatograms were made of some turpentines, organic peroxides, and epoxides, and sprayed to detect peroxides. Benzoyl peroxide, cumene hydroperoxide, and painters' turpentine gave the most prominent spots. Only one of the three epoxides tested, styrene oxide, showed peroxide. Many more peroxides were present in "aged" turpentine than in freshly prepared samples. As aged turpentine has most effect on fowl plasma α-lipoprotein, chemical differences between samples should be considered when turpentines are used in experimental pathology.
The effect of Mg++ on the ATPase activity of intact liver mitochondria
Authors: Cereijo-Santaló Roberto
Published: December 2009

The effect of 1 mM Mg++ on the hydrolysis of ATP by intact liver mitochondria was investigated. It was found that of nine commercial preparations of ATP tested, the hydrolysis of only one was stimulated by Mg++. It is suggested that this preparation of ATP contains as contaminant a factor capable of making mitochondria permeable to cations.
Studies on the biological control of glycogen metabolism in liver. III. Subcellular distribution of glycogen metabolizing enzymes
Authors: Maddaiah V. T. , Madsen N. B.
Published: December 2009

In a study of the subcellular distribution of the enzymes of the glycogen cycle in rat liver, glycogen synthetase was found in both the microsomal pellet and supernatant fractions, but the activity was always greater in the pellet than in the supernatant fraction. Variations in the concentration of liver glycogen, brought about by fasting and refeeding, did not alter this distribution. In agreement with the results of others, phosphorylase appeared almost entirely in the microsomal fraction, presumably bound to glycogen, when liver glycogen was high, or in the supernatant fraction when liver glycogen was low. These results indicate that synthetase and phosphorylase may be bound with different affinities or to different forms of glycogen.Regardless of whether the animals were fasted or fed, significant amounts of UDPG pyrophosphorylase activity appeared in the microsomal pellet fraction. The remainder of UDPG pyrophosphorylase and all of phosphoglucomutase activities were present in the microsomal supernatant fraction. As synthetase and phosphorylase are bound to glycogen, which in turn is known to be associated with the endoplasmic reticulum, the occurrence of UDPG pyrophosphorylase, synthetase, and phosphorylase in the microsomal fraction may have functional significance to the glycogen cycle.
Utilization of native primer by mammalian liver glycogen synthetase: primer efficiency in binding the enzyme and in catalysis
Authors: Vardanis A.
Published: December 2009

The particulate glycogen–glycogen synthetase complex isolated from mammalian liver is often strongly dependent on the addition of primer for activity. The present experiments offer an explanation for this behavior. Hepatic α-amylase, which is also adsorbed on the particle, can, even at the low temperatures (0–4°) of the preparatory procedure, hydrolyze the outer branches of particulate glycogen and thus reduce its efficiency as a primer. Synthetase activity of particulate glycogen prepared from the livers of starved animals is much more dependent on the addition of exogenous primer as compared to the enzyme from fed animals. Correspondingly, the livers of starved animals contain a lower amount of particulate glycogen and exhibit higher α-amylase activity.When particulate glycogen is rapidly prepared from fed animals, the glucose-6-P independent portion of its glycogen synthetase activity is only slightly increased by addition of extra primer. The glucose-6-P dependent activity of the same preparations, however, is doubled by addition of soluble glycogen, suggesting that the latter form of the synthetase is bound to glycogen in a partially inactive complex.The efficiency of a glycogen sample in binding the synthetase seems to be proportional to the ability of that sample to act as primer in the synthetase reaction. This finding strengthens the hypothesis that the enzyme is adsorbed to glycogen through its catalytic site, i.e. in an enzyme–substrate complex. It is evident, however, that in a number of cases this complex is only partially active since it exhibits varying degrees of dependence on added soluble primer.
Optical rotatory dispersion and absorbance–temperature studies on wheat embryo ribosomal ribonucleates
Authors: Wolfe Fred H. , Oikawa Kimio , Kay Cyril M.
Published: December 2009

Wheat embryo ribosomal RNA (rRNA) has been shown by optical rotatory dispersion (o.r.d.) and absorption–temperature measurements to possess a substantial secondary structure in solution which is stabilized by hydrogen bonding of paired bases in helical segments, and by nearest-neighbor base stacking in single-stranded segments of the molecule. Experimental conditions were established where single-strand stacked conformations predominated over base-paired regions. This state of affairs was effected by reducing the number of hydrogen-bonded nucleotides in RNA by any of three treatments: protonation, formylation, or reduction of the ionic strength of the medium to essentially zero. At the same time, use of the organic solvent ethylene glycol, which preferentially breaks hydrophobic bonds, has demonstrated that base stacking plays a significant role, as well, in the stabilization of the native conformation. Application of the empirical method of C. R. Cantor, S. R. Jaskunis, and I. Tinoco (J, Mol. Biol. 20, 39 (1966)), whereby it is possible to predict the optical rotatory properties of single-stranded polynucleotides from the corresponding properties of oligonucleotides, successfully demonstrated that wheat embryo rRNA, in the absence of salt, is predominantly in a single-stranded stacked conformation. From hyperchromicity data measured on RNA under conditions where hydrogen-bonding and base-stacking forces were delineated, the helical content of wheat embryo rRNA has been estimated as 65%. In view of the close similarity in the o.r.d. curves of RNA in salt solution and in the ribosome, it is concluded that RNA in the ribosome must be in a largely base-paired double-helical conformation, joined by single-stranded links.
Effect of massive X-irradiation on proteins and protein synthesis in peanut cotyledons
Authors: Huystee R. B. van
Published: December 2009

Peanut seeds were irradiated with 500 kR of X rays and stored for 6 weeks. The cotyledons from 3-day-old seedlings were harvested, and incubated with leucine-14C. The water-soluble protein content of those cotyledons was half to one-third that of the non-irradiated cotyledons. Protein biosynthesis in the irradiated cotyledons was equally reduced to one-third or less of control. Separation of the extracted proteins by acrylamide-gel electrophoresis suggested that there may be a larger amount of small-molecular proteins in the irradiated system. De novo biosynthesis after irradiation was restricted in all protein fractions. Enzyme activity was also severely restricted. No particular radiation-resistant isoenzyme of peroxidase could be detected.
Liver lipids of rats administered excessive amounts of retinol
Authors: Misra U. K.
Published: December 2009

Effect of intramuscular administration of 100 000 I.U. of retinol daily for 13 days on the liver lipid metabolism of young rats was studied. Intramuscular administration of excessive amounts of retinol did not affect the body weights or the daily food consumption. Retinol-treated rats showed a significant enlargement of the liver compared with controls. The values for liver total lipids, total cholesterol, total glycerides, total fatty acids, and retinol were 59.9 ± 0.9, 2.5 ± 0.1, 24.2 ± 1.3, 27.9 ± 1.8, and 1.35 ± 0.14 mg/g wet tissue, respectively, in retinol-treated compared with control values of 37.0 ± 0.9, 1.8 ± 0.06,9.5 ± 0.46, 17.6 ± 1.5, and 0.024 ± 0.008. The effect of excess retinol administration on liver neutral lipids and phospholipids was studied by thin-layer chromatography. Retinol administration caused significant increases in the concentrations of free cholesterol, esterifled cholesterol, monoglycerides, triglycerides, lysophosphatidylcholine, phosphatidylcholine, and phosphatidylethanolamine, and significant decreases in the concentration of phosphatidylinositol.
Kinetic studies of mutant human erythrocyte adenine phosphoribosyltransferases
Authors: Henderson J. Frank , Miller Helen R. , Kelley William N. , Rosenbloom Frederick M. , Seegmiller J. Edwin
Published: December 2009

The kinetic constants and reaction mechanism of human erythrocyte adenine phosphoribosyltransferase from individuals whose enzyme activities have high, intermediate, or low degrees of stability to heat inactivation, and in a human mutant with reduced activity of this enzyme, have been measured. The Michaelis constants for one or both substrates are different from normal in seven mutants.