bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution patterns of in vivo conversion products of injected estradiol-17β-4-14C and estrone-4-14C in the urines of the nonlaying and laying hen
Authors: Common R. H. , Mathur R. S. , Mulay Shree , Henneberry G. O.
Published: December 2009

Estradiol-17β-4-14C was injected into a mature hen when it was not in lay and when it was in lay. In each instance the major radioactive conversion products in the urine were estrone and estradiol-17α. The percentage of the total radioactive phenolic steroids present in the urine as estradiol-17β was higher, and the percentages present as estradiol-17α and as estrone were lower when the hen was not in lay than when the hen was in lay. Estrone-4-14C was injected into a mature hen in a second similar experiment, and the major radioactive conversion products in the urine were estradiol-17β and estradiol-17α. As in the first experiment, the percentage of the total radioactive phenolic steroids present in the urine as estradiol-17β was higher and the percentages present as estradiol-17α and as estrone were lower when the hen was not in lay than when she was in lay.Irrespective of whether estrone-4-14C or estradiol-17β-4-14C were injected, the major radioactive phenolic steroids in the urine were estradiol-17β, estrone, and estradiol-17α, in that order, when the hen was not in lay, and estrone and estradiol-17β or estradiol-17α, in that order, when the hen was in lay.
Glyoxaiase I, a lyase or an oxidoreductiye isomerase?
Authors: Davis K. A. , Williams G. R.
Published: December 2009

The 200-fold purification of glyoxaiase I (EC 4.4.1.5) from calf liver is described. This enzyme exhibits two marked anomalies in its kinetic behavior. There is an initial lag phase of a few seconds, and the plot of velocity versus enzyme concentration is nonlinear, reaching a plateau value. These features are correlated with the kinetics of formation of the hemimercaptal of glutathione and methylglyoxal, suggesting that this adduct is the true substrate of glyoxaiase I.
A notation for the amino acids based on the genetic code
Authors: Black J. A.
Published: December 2009

A notation for the amino acids based on the genetic code is presented together with some examples of its application in a simple visual process for the detection of genetic events which are known to occur during the evolution of proteins.
Chemical modification of wheat gluten with hydrazine
Authors: Krull L. H. , Wall J. S.
Published: December 2009

The side-chain amide groups of wheat gluten were converted to hydrazide groups by reaction with hydrazine in aqueous and anhydrous systems. When the reaction was carried out in aqueous hydrazine, extensive hydrolysis of side-chain, as well as peptide-amide groups occurred. Anhydrous hydrazine, when used as solvent and reactant, increased the extent of hydrazide formation and also decreased the peptide-amide cleavage. When the hydrazine concentration was lowered by use of dimethyl sulfoxide as solvent, peptide cleavage was minimal and a good yield of side-chain hydrazide was obtained.
Metabolic and electrophoretic studies of rat liver sorbitol dehydrogenase
Authors: Murray R. K. , Gadacz I. , Bach M. , Hardin S. , Morris H. P.
Published: December 2009

The effect of various factors on the activity of rat liver sorbitol dehydrogenase was investigated. The activity of the enzyme (expressed per gram of tissue) was similar in the livers of adult male and female rats and was not affected by adrenalectomy, cortisone injection, or hypophysectomy. Different modes of administration of sorbitol also produced little change in activity. The enzyme activity declined significantly during 1 week of starvation. Activity was low in foetal liver and rose gradually during the postnatal period to reach adult levels by approximately 40 days after birth. Sorbitol dehydrogenase activity in the moderately well-differentiated Morris hepatoma 5123 T.C. was studied and found to be approximately 40% of that of normal liver. Using the technique of starch-gel electrophoresis in sodium borate, the rat liver enzyme was found to occur in multiple molecular forms. The electrophoretic pattern of the rat liver enzyme in sodium borate was not affected by a variety of metabolic conditions and was also identical in the hepatoma. From a study of various factors influencing the electrophoretic separation of rat liver sorbitol dehydrogenase, it is concluded that the multiple molecular forms are similar species of the enzyme and that interaction with a starch–borate complex may be important in their resolution.
Pyruvate carboxylase of Aspergillus niger: kinetic study of a biotin-containg carboxylase
Authors: Feir Helen A. , Suzuki Isamu
Published: December 2009

Pyruvate carboxylase was partially purified from Aspergillus niger and the properties were studied. The enzyme was found to be cold-labile and protected by 25% glycerol. The pH optimum was determined to be 7.9–8.0. The enzyme was shown to be a biotin-containing enzyme by its inactivation by avidin and protection against such inactivation by biotin. The enzyme activity was stimulated by K+ ions and inhibited by Na+ ions. Acetyl-CoA had no effect on enzyme activity, but L-aspartate was inhibitory. Apparent Michaelis constants were determined for the substrates and metal cofactor involved, i.e. pyruvate, ATP, bicarbonate, and Mg2+.Initial-velocity studies were carried out at varied concentrations of substrates in order to determine the true Michaelis constants and to elucidate the kinetic mechanism of reaction. Product-inhibition studies were carried out with each product (ADP, Pi, and oxalacetate) in combination with every substrate (ATP, bicarbonate, and pyruvate). From these kinetic studies and the existing knowledge on biotin-containing carboxylases, a mechanism was proposed for the action of pyruvate carboxylase which involves three independently active sites on the enzyme, one for each substrate. The interactions between the sites were visualized as being mediated by carboxybiotin formed on the enzyme. A steady-state rate equation was derived that satisfied kinetic results obtained.
The gelation of β-lactoglobulin A by ethylene glycol
Authors: Kientz Marvin L. , Bigelow Charles C.
Published: December 2009

The unfolding of β-lactoglobulin A by ethylene glycol concentrations above 60% is shown to be followed by either the formation of a clear gel or a turbid aggregate. Both of these can apparently be formed either from the most completely unfolded form of the molecule which occurs around 80% glycol, or from a more structured conformation which occurs at very high glycol concentrations (around 90%). The gel and the aggregate form under different conditions of pH and ionic strength, so that it seems that the most important factor controlling their production is electrostatic.
Studies on the extractability of brain gangliosides
Authors: Spence M. W.
Published: December 2009

Ganglioside extractability from rat brain homogenates by chloroform/methanol can be selectively reduced by lowering the tissue concentration of monovalent cations by dialysis or washing. In this study, no specificity for either Na+ or K+ is observed, either during dialysis or on the addition of these ions to deionized tissues. Charged organic amines are most effective in restoring ganglioside extract-ability when they have a structure analogous to choline or isopropylamine. The presence of a negative charge close to the nitrogen markedly reduces their effectiveness. Lowering the pH of normal and deionized microsomal preparations prior to extraction also decreases ganglioside extractability, with a minimum at pH 2.5 and a return of extractability at pH 0.5–1.0. A slight return of extractability in deionized preparations is observed in the alkaline range. It is proposed that lowering the tissue pH or decreasing the tissue content of monovalent cations allows an electrostatic association between the negatively charged ganglioside and positively charged groups on proteins.
Occurrence of ascorbic acid in the yeast Lipomyces starkeyi
Authors: Heick H. M. C. , Stewart H. B. , Graff G. L. A. , Humpers J. E. C.
Published: December 2009

Ascorbic acid was identified in cultures of the yeast Lipomyces starkeyi. The acid was identified by preparing the Roe and Kuether chromogen and comparing its infrared spectrum with the spectra of chromogens derived from ascorbic and araboascorbic acids. After 5 days of growth on glucose medium the ascorbic acid concentration in cellular extracts was 214 μg/g wet weight.
Resolution of mitochondrial structural proteins by discontinuous electrophoresis in acrylamide gels
Authors: Lejsek K. , Lusena C. V.
Published: December 2009

The presence of many bands in preparations of rat liver and yeast mitochondrial structural proteins (MSP) is shown by disc (discontinuous) electrophoresis in acrylamide gel at pH 3.3 and at pH 9.9. This resolution is better than in previously reported acidic systems and is shown for the first time in a basic system. Purification of MSP with methanol – trichloroacetic acid and 8 M urea did not change the patterns except for the removal of fast-moving minor bands detectable at pH 3.3 in preparations from rat liver mitochondria.
Metabolism of fatty acids in the southern elephant seal Mirounga leonina (L.)
Authors: Bryden M. M. , Stokes G. B.
Published: December 2009

In general, the composition of the blubber of the southern elephant seal, determined by gas–liquid chromatography, is similar to that of other marine mammals. In this regard, the present work disagrees with an earlier study made on an individual of this species. The marked disappearance of the long-chain polyunsaturated acids in both the nursing cow and fasting pup suggests catabolism of these acids during nonfeeding periods. Support is given here for the contention that some fatty acids are transferred intact from the depot fat of the seal cow to her pup via the milk.
Triglyceride structure of human milk fat
Authors: Breckenridge W. C. , Marai L. , Kuksis A.
Published: December 2009

The triglycerides of the fat globules of human milk were resolved by thin-layer chromatography on silica gel impregnated with silver nitrate. The chemical structure of the glycerides was determined by gas chromatography of the glycerides and fatty acids and by a stereospecific analysis of total milk fat sample. The major triglycerides of human milk fat contained 48–54 acyl carbons which were made up of C12–C22 acids of various degrees of unsaturation. The fully saturated triglycerides (6–8%) contained mainly sn-glycerol 1-stearate 2-palmitate esterified at position 3 with C14–C18 acids. The monoenoic triglycerides (25–27%) were comprised mainly of sn-glycerol 1-oleate 2-palmitate esterified at position 3 to C12–C18 acids, as well as their racemates. The dienes (24–33%) were made up largely of sn-glycerol 1-stearate 2,3-dioleate and 2-palmitate 1,3-dioleate. The trienes (18–20%) contained mostly sn-glycerol 1,2,3-trioleate and 1-oleate 2-palmitate 3-linoleate. The tetraenes (7–21%) were identified as mainly sn-glycerol 1,2-dioleate 3-linoleate and 1-palmitate 2,3-dilinoleate. Arachidonic acid was found in the polyene fraction (6%) in the 2-position, while the linolenic acid was preferentially associated with position 3 of the tetraenes.
Bovine hepatic carboxylesterases chromatographic fractionation, gel filtration, and molecular weight estimation
Authors: Ecobichon D. J.
Published: December 2009

The carboxylesterase activity of bovine liver was fractionated by DEAE-cellulose chromatography into two peaks of activity. Electrophoresis in starch gel showed that the peak eluted first was composed of a group of five electrophoretically slow bands while the second peak was a single, rapidly migrating band. Gel filtration of the crude extract on Sephadex G-100 and G-200 yielded a single peak of esterase activity containing both the electrophoretically slow and fast bands. The determination of molecular weights by gel filtration on Sephadex G-200 and G-100 yielded estimates of 52 000 and 55 000, respectively. The molecular weight estimates of the DEAE-cellulose fractionated electrophoretically slow and fast bands on Sephadex G-100 were identical, namely 55 000.
The properties of a glutamate decarboxylase from Physarum polycephalum
Authors: Nations Claude , Anthony R. M.
Published: December 2009

An enzyme that mediates the decarboxylation of L-glutamic acid is endogenous to Physarum polycephalum. The enzyme is similar to mouse brain glutamate decarboxylase with respect to its Michaelis–Menton constant (2.1 × 10−3 M), pattern of response to increasing substrate concentrations, and the influence of halide anions on its activity. Its optimum pH range (5.6–6.0) is nearer the values reported by a variety of workers for preparations obtained from higher plants. The enzyme exhibits a thermal stability greater than that reported for the glutamate decarboxylase from any other organism, retaining full activity when heat-treated at temperatures as high as 60 °C.
Some chemical and biochemical properties of selenomethionine
Authors: Shepherd Lois , Huber R. E.
Published: December 2009

Some chemical properties important to the biochemistry of the amino acid analogue selenomethionine were studied. It was found to be less soluble in demineralized distilled water, much less stable to acid hydrolysis, and of a different infrared spectrum than methionine itself. Selenomethionine reacted much more rapidly with cyanogen bromide to form homoserine than did methionine. A method of diagonal chromatography using cyanogen bromide vapors was introduced as a possible means of locating selenomethionine molecules in proteins. The results are discussed with regard to the possible effect of selenomethionine on protein structure and function, and to the chemical means of locating selenomethionine in selenoproteins.
Studies on plasminogen. VII. Mechanism of activation of bovine plasminogen
Authors: Hoepfinger Lynn M. , Mertz Edwin T.
Published: December 2009

Native bovine plasminogen is converted to an altered plasminogen and then to plasmin I by either urokinase, plasmin I, or plasmin II. Plasmin I is converted by self-catalysis to plasmin II. Plasmin II degrades itself to the inactive fragment peptide A. In the conversion of native plasminogen to plasmin I, a peptide bond is cleaved giving two chains (designated A1 and B) which are held together by one or more disulfide linkages. When plasmin I is converted to plasmin II, a polypeptide chain is removed from the A1 chain of plasmin I to give plasmin II containing A2 and B chains. When plasmin II is converted to peptide A, most of the B chain is lost. During activation of bovine plasminogen, a molecular entity (termed polypeptide C) with an apparent molecular weight larger than the plasminogen is formed. It is a continuous heterogeneous polypeptide chain.
Delayed effects of S-β-aminoethylisothiouronium bromide hydrobromide (AET) administration on lipid metabolism
Authors: Naqvi Saida , Kumar K. S. , Venkitasubramanian T. A.
Published: December 2009

Various doses of S-β-aminoethylisothiouronium bromide hydrobromide (AET), one of the most promising radioprotectors to date, were administered to rats by a single intraperitoneal injection. Doses of up to 200 mg/kg body weight were tolerated but doses of 250 mg/kg body weight and above were toxic. There was accumulation of lipids in liver of rats 30 days after AET administration. Acetate-1-14C incorporation into total lipids, fatty acids, and nonsaponifiable lipids of liver, kidney, and spleen was inhibited by AET administration.
Studies on 2′,3′-cyclic nucleotide-3′-phosphohydrolase from brain
Authors: Olafson Robert W. , Drummond George I. , Lee Jack F.
Published: December 2009

Studies on a 2′,3′-cyclic nucleotide-3′-phosphohydrolase are presented. Bovine brain white matter was fractionated by differential centrifugation and sucrose density gradient techniques. The phosphohydrolase was distributed throughout all primary fractions: nuclear, mitochondrial, and microsomal. When these fractions were subjected to sucrose density gradient centrifugation the enzyme appeared only in the myelin-containing layers. Brains of newborn rats were essentially devoid of phosphohydrolase activity and the content rose rapidly during the 12th and 25th days, coinciding precisely with the development of myelin. Mutant 'quaking' mice whose brains are partially deficient in myelin were also partially deficient in enzyme activity. The data provide evidence that the phosphohydrolase is associated with myelin.The enzyme opens the cyclic phosphodiester linkage of Ap(Ap)2A cyclic P and Ap(Ap)6A cyclic P without rupture of internucleotide bonds. The enzyme also hydrolyzed the 2′,3′-cyclic phosphorothioates of uridine and guanosine. The Km for adenosine 2′,3′-cyclic phosphate was determined to be 1.9 × 10−3 M, an inordinately high value, and since nothing is known about the physiological role of the enzyme, the possibility is raised that the true substrate may not be a cyclic nucleotide.
Decreased monoamine oxidase activity in liver of iron-deficient rats
Authors: Symes A. L. , Sourkes T. L. , Youdim M. B. H. , Gregoriadis G. , Birnbaum H.
Published: December 2009

Chronic nutritional deficiency of iron in the rat results in a decrease of 18–31% in the monoamine oxidase activity of the liver. Prolonged feeding of a diet low in copper was without effect on the enzyme, although the concentration of ceruloplasmin in the plasma and of copper in the liver declined.Possible roles of iron in the action of monoamine oxidase are discussed. The inhibitory actions of three iron-chelating agents on monoamine oxidase preparations are consistent with a function of iron in the oxidation of monoamines.
Plasma peroxidase activity in avian erythroblastosis
Authors: Darcel C. le Q. , Bide R. W.
Published: December 2009

The peroxidase activity of the plasma of birds with erythroblastosis was closely related to the heme content. Plasma heme proteins were hemoglobin and its derivatives only. The majority of the hemoglobin was found as the hemoglobin–haptoglobin complex, but quantities of free hemoglobin and methemalbumin were also present. The plasma peroxidase level would appear to be an index of the progress of the disease.
Studies on acid deoxyribonuclease from brain
Authors: Rosenbluth R. , Sung Shan-Ching
Published: December 2009

An endonucleolytic acid DNase was purified from beef brain. It resembled spleen DNase II with respect to the properties studied: preference for double-strandedness, products of hydrolysis, pH optima, effects of some salts, and the effect of high substrate concentrations on the rate of release of acid-soluble nucleotides. The latter three points are discussed.
Regulation of onset of rapid hemoglobin synthesis in the blood islands of chick blastodiscs by δ-aminolevulinic acid
Authors: Wainwright S. D. , Wainwright Lillian K.
Published: December 2009

A supplement of 10−3 M δ-aminolevulinic acid markedly stimulated hemoglobin synthesis over a critical 4-h period in the blood islands of chick blastodiscs explanted at the 6-somite (27–30 h) stage of development onto both complex and minimal media. Stimulation was no longer significant at 24 h on both minimal and complex media.
Amino-terminal groups in zymogen activation: effect of nitrous acid on pepsin
Authors: Hofmann T.
Published: December 2009

Nitrous acid rapidly deaminates the N-terminal isoleucine residue of pepsin. The enzyme retains more than 60% of its activity. The loss of 30–40% activity can be ascribed to the reaction of two tryptophan residues with nitrous acid. The single lysine residue is also deaminated. These results are in contrast to those obtained with serine proteinases where nitrous acid causes inactivation due to the deamination of the N-terminal amino group.
A modified fractionation procedure for avian erythrocyte histones
Authors: Adams G. H. M. , Neelin J. M.
Published: December 2009

The fractionation method of Vidali and Neelin for avian erythrocyte histones was modified to reduce the time required to obtain clean fractions of serine-rich and arginine-rich histones. Histones were extracted from washed nuclei in one step with 0.20 M HCl. The lysine-rich and the moderately lysine-rich histones were fractionated by cation-exchange chromatography but the serine-rich and arginine-rich histones were eluted together. These histones were separated by subsequent exclusion chromatography.
The isolation and properties of the skin-reactive substance in Aedes aegypti oral secretion
Authors: Newsome W. H. , Jones J. K. N. , French F. E. , West A. S.
Published: December 2009

The skin-reactive substance present in the oral secretion of Aedes aegypti mosquitos was isolated by gel filtration chromatography and found to be a protein of high molecular weight designated as F-1. Amino acid analysis of the protein revealed relatively high proportions of glycine (34%) and proline (11%). The active fraction contained 9% carbohydrate and less than 1% amino sugar, sialic acid, or phosphorus. A random coil structure was suggested for F-1 on the basis of optical rotation and infrared data. A linear relation was established between the diameter of the immediate skin reaction and the logarithm of the weight of F-1 injected. F-1 was completely inactivated by incubation at pH 2.5. A low molecular weight fraction was separated from inactivated F-1 and its amino acid composition was determined.
Folate derivatives in healthy and rust-infected primary leaves of wheat
Authors: Rohringer R. , Kim W. K. , Samborski D. J.
Published: December 2009

Six days after inoculation, crude extracts were prepared from healthy and rust-infected wheat leaves of a susceptible line and from healthy and rust-infected wheat leaves of a resistant line. Extracts from rust-infected leaves of both lines contained 50% more folates, active as growth factors for Lactobacillus casei, than did those from healthy leaves. Rust-infected leaves did not differ from healthy leaves in their content of folates active as growth factors for Streptococcus faecalis and Pediococcus cerevisiae.All extracts were fractionated on DEAE-cellulose columns. The eluate fractions were treated with chicken pancreas conjugase and assayed with L. casei. All extracts yielded similar folate profiles consisting of five major and three minor peaks. Conjugase treatment and differential assay of the peak fractions with L. casei, S. faecalis, and P. cerevisiae indicated that the eluates contained folates methylated at N-5 and folates formylated at N-10 in various states of oxidation and conjugation. The eluates also contained a compound believed to be 5-formyltetrahydropteroylglutamate, small amounts of pteroylglutamate, traces of tetrahydropteroylglutamate, and several unidentified folates.The increase of folate levels in rust-infected leaves was due almost entirely to increases of 5-methyl-tetrahydropteroylgiutamate and its conjugates. The folate composition of resistant-reacting leaves did not differ appreciably from that of susceptible-reacting leaves.Radioactivity was not incorporated into either 5-methyltetrahydropteroyltriglutamate or into methionine when 5-[methyl-14C]-tetrahydropteroylglutamate was fed to wheat leaves.
Lactic dehydrogenase isozyme distributions in various cell types of the mammalian liver
Authors: Palmer Lars S. , Karlsson Börje W.
Published: December 2009

From livers of mouse, rat, cat, rabbit, hamster, guinea pig, cow, pig, and cod, two rather well-defined tissue fractions have been prepared: one rich in and the other devoid of connective tissue. The amount of sulfate in a particular cell fraction mirrored the amount of chondroitin sulfate present, and thus could be taken as an approximate measure of the connective tissue content. Other evidence to support the identification of this fraction as connective-tissue-rich was its insolubility, resistance to homogenization, and its digestibility with collagenase.The lactic dehydrogenase (LDH) isozyme patterns of extracts from whole organs and from the two tissue fractions demonstrate interspecies and intraspecies differences. Within a particular animal organ, different LDH isozyme patterns are predominant for each cell population. The most outstanding example is the mouse liver, where the connective-tissue-poor fraction is almost totally composed of LDH isozyme 5 (>95%). Calculations, performed with the binomial distribution of isozyme activities in the two tissue fractions, indicate that in the rabbit, hamster, guinea pig, and cat, also, the liver is composed of several cell lines, each with a predominant LDH isozyme pattern. 'Liver cells' exhibit isozyme activities which fit binomial distributions much better than do the 'connective tissue' fractions, indicating that the former fraction contains fewer different cell lines. The species differences observed may depend then upon the presence of varying numbers of cell lines, each exhibiting a predominant characteristic LDH isozyme pattern.
Amino-terminal-blocked tripeptide analogues of the active site of α-chymotrypsin
Authors: Houston M. , Viswanatha T.
Published: December 2009

Amino-terminal-blocked peptide analogues of the active site of α-chymotrypsin, viz. N-benzyloxycarbonyl-Asp-Ser-Gly and N-benzyloxycarbonyl-Gly-Asp-Ser, have been synthesized. These synthetic peptide analogues function as poor acyl acceptors during their reaction with furylacryloylimidazole. However, the presence of imidazole facilitated a rapid acylation of the serine hydroxyl of these peptides. The effect of various types of treatment on the amino add composition and sequence of the O-furylacryloyl derivatives of the peptides has been investigated.
The influence of aminonucleoside on polysome patterns of rat liver
Authors: Kovacs E. S. , Kung S. D. , Moscarello M. A.
Published: December 2009

Intravenous injection of the aminonucleoside of puromycin has been shown to affect the size distribution of polysomes isolated from rat liver. A marked shift to higher aggregates has been observed in both free and membrane-bound polysomes, with a more pronounced shift in the free polysomes. The shift to higher aggregates was observed by both density gradient and analytical ultracentrifugation analyses.
A comparative study of adrenal steroid biosynthesis in two species of monkeys
Authors: Nicola A. F. de , Birmingham M. K.
Published: December 2009

Adrenal slices of Macaca speciosa (M.s.) and Saimiri sciureus (S.S.), incubated for 4 h in Krebs–Ringer bicarbonate glucose medium with radioactive pregnenolone, progesterone, deoxycorticosterone (DOC), and corticosterone, displayed marked differences between the two glands in the biotransformation of the substrates. M.s. adrenals formed aldosterone in high yield from all the substrates added; by contrast, S.s. adrenals yielded no aldosterone from any of the substrates, but amounts of corticosterone were produced greatly exceeding those obtained with M.s. glands. Cortisol was also produced in greater yield by S.s. glands, and pregnenolone was by far the better substrate. 11β-Hydroxyandrostenedione, derived from pregnenolone, was only obtained from S.s. glands as was 11-dehydrocorticosterone, derived from progesterone, DOC, and corticosterone. 18-Hydroxydeoxycorticosterone (18-OH-DOC) was isolated with DOC in the presence of nicotinamide after incubation of S.s., but not M.s., adrenals. The biotransformation of radioactive 18-OH-DOC was studied only with M.s. adrenals. Aldosterone was obtained in 5% and 18-hydroxycorticosterone in 0.6% yield; no other conversion products were detected.
Gene action in the human haptoglobins. III. Isolation of the α chains as single gene products. Isolation molecular weight, and amino acid composition of α and β chains
Authors: Black J. A. , Chan G. F Q. , Hew C. L. , Dixon G. H.
Published: December 2009

A modified method for the preparation of large quantities (1–10 g) of human haptoglobin (Hp) from the ascites fluid of a single patient has been developed. By selection of a heterozygous individual of genotype Hp1S/Hp2(F,S), and taking advantage of the different molecular sizes of the polypeptide gene products haptoglobin α1S and α2(F,S), it is possible to separate by Sephadex G-75 chromatography the reduced and alkylated polypeptide products of the single genes Hp1S and Hp2(F,S) for subsequent characterization and sequence analysis. The second polypeptide chain of haptoglobin, the β chain, is also obtained pure and in good yield by this procedure. The molecular weights of the β and α2 chains were determined after modification of the amino groups with succinic anhydride to reverse the extensive aggregation of reduced and alkylated β and α2 chains in neutral and alkaline solutions. Amino acid and carbohydrate compositions of the separated chains have been determined and it is shown that the empirical polypeptide chain constitution of haptoglobin 2–1 is (2 × β + α2 + α1).
Aldolase activity in the cell-free extract of the protozoan Leishmania donovani
Authors: Ghosh Dilip K. , Datta Asoke G.
Published: December 2009

Aldolase has been shown to be present in the cell-free extract of Leishmania donovani. In view of its metal requirement and other properties it resembles the class I type of aldolases. Unlike bacterial aldolase, however, it is not inhibited by α,α′-dipyridyl and EDTA. It is insensitive to the well-known –SH reagents. It is strongly inhibited by Cu2+ ions and to a lesser degree by Zn2+ and Mn2+ ions. The optimum pH of the enzyme is 7.2.
Inhibition of monoamine oxidase by sodium pentobarbital
Authors: Quevedo E. , D'Iorio A.
Published: December 2009

A single intraperitoneal injection of 30, 60, or 90 mg/kg of sodium pentobarbital into male rats produced an appreciable inhibition of monoamine oxidase activity of liver and heart. The brain and kidney activities were practically unaffected. Chronic administration of pentobarbital, 30 mg/kg daily for 20 days, did, however, produce an inhibition of brain monoamine oxidase (MAO) which was maximal 48 h after the last injection. In all other experiments with a single dose of barbiturate the maximal inhibition of MAO appeared 15–30 min after treatment.Sodium pentobarbital inhibited MAO activity in vitro when added to a liver mitochondrial preparation. High concentrations of barbiturate had to be used for the in vitro experiments. The Ki value for sodium pentobarbital was 1.21 × 10−3 M while the Km was 1.6 × 10−5 M. The observed inhibition was of a competitive nature. The inhibition is comparable with that observed for some flavoenzymes following addition of barbiturates.
Phosphonolipids. XXII. Synthesis of phosphonic acid analogues of L-α-(N-methyl)cephalins
Authors: Baer Erich , Pavanaram Sripada K.
Published: December 2009

Distearoyl and dipalmitoyl L-α-glyceryl-(N-methyl-2-aminoethyl)phosphonates were synthesized by phosphonylating D-α,β-distearin and D-α,β-dipalmitin, respectively, with (N-carbobenzoxy,N-methyl-2-aminoethyl)phosphonic acid monochloride and triethylamine, and removing the protective carbobenzoxy group by catalytic hydrogenolysis.
Phosphofructokinase and glycolysis in the livers of rats fed a thrombogenic diet
Authors: Simard-Duquesne N.
Published: December 2009

Liver supernatant phosphofructokinase activity is increased in rats fed a thrombogenic diet at about the same time as the incidence of endotoxin-induced thrombosis is known to increase. In the livers of these rats, the Pasteur effect, as determined by the production of lactic acid in a reconstituted system containing a high-speed supernatant with and without the mitochondrial fraction, is significantly decreased.
Enzymes involved in the metabolism of thiosulfate by Thiobacillus thioparus. III. Properties of thiosulfate-oxidizing enzyme and proposed pathway of thiosulfate oxidation
Authors: Lyric Ronald M. , Suzuki Isamu
Published: December 2009

Thiosulfate-oxidizing enzyme was purified from Thiobacillus thioparus extracts 120- to 160-fold and the properties were studied. The enzyme had a molecular weight of 115 000 and contained 2 moles of non-heme iron. Ferricyanide was a much better electron acceptor than cytochrome c, but with cytochrome c the Km for thiosulfate was lowered from 0.1 mM to 5 μM and the pH response of the enzyme changed. Sulfite was a very strong inhibitor destroying 50% of the activity at 5 μM. The inhibition was time-dependent and essentially irreversible. Properties of the T. thioparus enzyme were compared to those of thiosulfate-oxidizing enzyme isolated from Thiobacillus neapolitanus and Ferrobacillus ferrooxidans. A pathway of thiosulfate oxidation is proposed, and metabolic roles of various enzymes studied in T. thioparus are discussed.
Acetyl-L-alanyl-L-alanyl-L-alanine methyl ester: a new highly specific elastase substrate
Authors: Gertler A. , Hofmann T.
Published: December 2009

Acetyl-L-alanyl-L-alanyl-L-alanine methyl ester is a highly specific esteratic substrate for elastase. It is only slowly hydrolyzed by trypsin and α-chymotrypsin (0.13 and 1.2%, respectively, of the rate of elastase), and can be used in crude preparations and for the study of proelastase activation. At pH 8.0 and 25°, KM = 0.43 mM; kcat = 73 s−1 and is independent of pH between 7.5 and 10.5. Acetyl-L-alanine methyl ester is a poor substrate with KM 153 mM and kcat 6.7 s−1.
In vitro protein synthesis directed by R17 viral ribonucleic acid. III. A new assay method for cell-free protein synthesis based on a phenylthiohydantoin procedure
Authors: Igarashi S. J. , Paranchych W.
Published: December 2009

A new method of assaying cell-free polypeptide synthesis was sought, in order to make it possible to measure peptide synthesis regardless of the solubility of products in aqueous solvent. By direct application of Edman's degradation procedure, the phenylthiohydantoins of free unreacted amino acids, as well as of amino terminal residues of peptides synthesized in a cell-free system, were extracted, and the quantity of amino acids incorporated into peptide was measured. With this method (liquid-phase method), it was discovered that in our cell-free system, lysine and phenylalanine were apparently polymerized at the same rate in the presence of the corresponding mRNA. There was also an appreciable amount of amino acid polymerization directed by R17 viral RNA whose products are mostly soluble in acid. The liquid-phase method was successfully modified so that all assay procedures could take place on filter paper. Thus it became possible to process a large number of samples simultaneously.
Relationship between peroxidase, catalase, and protein synthesis during cellular development in cell cultures of peanut
Authors: Verma D. P. S. , Huystee R. B. Van
Published: December 2009

In a suspension culture of peanut cotyledons (Arachis hypogaea L.) the rate of protein synthesis decreased as the cell mass increased in diameter, with a decrease in free amino acids except in a cell mass of 0.15–0.5 mm. A high level of catalase and low level of peroxidase activity was related to a higher rate of protein synthesis in single cell (< 0.15 mm) fractions.Both quantitative and qualitative differences in peroxidase and catalase enzymes exist between cell masses of different sizes. Analysis by polyacrylamide gel electrophoresis reveals the molecular heterogeneity of these enzymes in different cell masses. The appearance of a new peroxidase isozyme with a concomitant disappearance of a catalase isozyme was related to the cellular differentiation in a cell mass of > 0.5 mm in diameter. Another peroxidase isozyme appeared in a cell mass of 2–4 mm in diameter. Quantitatively there was a significant increase in peroxidase with a decrease in catalase activity between cell clumps of increasing sizes.
Effect of fluoride on ribosomes and ribonuclease from corn roots
Authors: Chang Chong W.
Published: December 2009

A study was made of ribosomes and ribonuclease in the roots of corn seedlings aged by fluoride. Fluoride induced a reduction of ribosome content in which a decrease in polysome level was accompanied by an increase in number and concentration of monosomes and subunits combined. Fluoride increased the specific activity of ribonuclease, probably associated with ribosomal protein. This enhanced activity was likely due to enzyme activation caused by fluoride. Sucrose density gradient analyses demonstrated that ribosome fractions contained a mixture of heterogeneous RNA components.
A new isolation and structure for the endotoxin from Microcystis aeruginosa NRC-1
Authors: Murthy J. Rama , Capindale J. B.
Published: December 2009

The endotoxin from the blue–green alga Microcystis aeruginosa NRC-1 has been isolated as its ammonium salt by a new procedure involving solvent extraction and elution from DEAE-Sephadex A-25. The intraperitoneal LD100 of this toxin preparation for mice was 0.1 mg/kg body weight. The product is a white solid which appears to be chromatographically and electrophoretically homogeneous. This toxin produces similar symptoms in mice to those described originally for the toxic material from the same algal strain. Analysis of the toxin hydrolysate indicates a more complex structure since seven more amino acids have been found, including tyrosine, proline, and arginine, in addition to the seven reported before.
Terminal deoxyribonucleotidyltransferase from nuclei of rat intestinal mucosa
Authors: Leung F. Y. T. , Zbarsky S. H.
Published: December 2009

A terminal deoxyribonucleotidyltransferase has been isolated from extracts of nuclei of rat intestinal mucosa. The enzyme was obtained in partially purified form by rechromatography of material with DNA polymerase activity isolated previously by chromatography of the nuclear extract on DEAE-cellulose. The enzyme, which required heat-denatured DNA as a primer, catalyzed the incorporation of radioactivity from a single labelled deoxyribonucleoside triphosphate into the DNA product. The incorporation was inhibited up to 70% in the presence of all four complementary deoxyribonucleoside triphosphates. Evidence has been presented based on the release of radioactivity from the DNA product during its hydrolysis by snake venom phosphodiesterase which indicates that the enzyme catalyzes the addition of deoxyribonucleotides to the 3′-OH terminus of heat-denatured DNA. The properties of the enzyme are those of a terminal deoxyribonucleotidyltransferase as distinct from the replicative transferase, DNA polymerase.
The biosynthesis of 18-hydroxycorticosterone from exogenous corticosterone by teleost fish adrenocortical tissue in vitro
Authors: Sandor T. , Chan S. W. C. , Phillips J. G. , Ensor D. , Henderson I. W. , Jones I. Chester
Published: December 2009

Incubation of homogenized head kidney tissue of the cod (Gadus morhua) and the haddock (Melanogrammus aeglefinus) with tritiated corticosterone resulted in the formation of small amounts of 18-hydroxycorticosterone (cod 0.04%, haddock 0.012% transformation per 6 g head kidney tissue per 4 h), in the presence of excess NADPH. Incubation of European eel (Anguilla anguilla) posterior vein and head kidney "mitochondria" with corticosterone-4-14C, in the presence of excess substrate and NADPH, also gave rise to 18-hydroxycorticosterone (fresh-water-adapted animals, 0.13% per mitochondria equivalent to 756 mg tissue per 2 h; animals adapted to sea water for 48 h, 0.09% per mitochondria equivalent to 456 mg tissue per 2 h). The biosynthetic, isotopically labelled 18-hydroxycorticosterone was identified by serial oxidation. Head kidneys of both the cod and haddock transformed corticosterone to cortisol. However, the unequivocal presence of aldosterone could not be shown in any of these experiments.
Identification and characterization of phospholipase D in a unicellular red alga (Porphyridium cruentum)
Authors: Antia N. J. , Bilinski E. , Lau Y. C.
Published: December 2009

Axenically cultured cells of Porphyridium cruentum were assayed for enzymes catalyzing the hydrolysis of lecithin. The sonicated cells showed virtually exclusive and complete conversion of 14C-choline-labelled lecithin to 14C-choline, with no significant formation of glycerylphosphorylcholine or phosphorylcholine. The enzymatic activity showed a sharp pH optimum at 7.0, and was strongly inhibited by chelating agents (two types), sulfhydryl-group binding reagents (three types), and surface-active agents (anionic and non-ionic). The inhibition from ethylenediamine tetraacetate (EDTA) was reversed by Ca2+ or Sr2+ but not by Mg2+ or Ba2+, and that from —SH binding reagents was reversed by dithiothreitol. Heavy metal ions (Zn2+, Cu2+, Ba2+, Co2+, Mn2+, Fe2+) inhibited the activity, Ca2+ caused stimulation, while Mg2+ and Sr2+ had little effect. The results indicate the occurrence of a pH and heavy-metal ion sensitive, Ca2+-(or Sr2+-) requiring phospholipase D in the red alga, and the involvement of sulfhydryl groups in the expression of its activity. The algal enzyme resembles those from higher plants in its Ca2+ requirement and sensitivity to EDTA and organomercurial sulfhydryl binding reagent, but differs markedly in its optimum pH and several other properties.
High efficiency of oxidative phosphorylation in mitochondria of wheat
Authors: Sarkissian Igor V. , Srivastava Hari K.
Published: December 2009

Mitochondria of young seedlings of a wheat hybrid 31MS × 28 exhibited high efficiency of oxidative phosphorylation. The ADP:O ratios estimated polarographically approached or were equivalent to 6, 4, and 5 with α-ketoglutarate, succinate, and malate, respectively. The respiratory control values with these substrates were about 7.5, 4.5, and 2.9. When assayed manometricafly, the P:O ratios with α-ketoglutarate as substrate and 10 min of reaction time were between 5.4 and 5.8. ADP was utilized almost exclusively in oxidative phosphorylation; microbial contamination in phosphorylating reaction mixtures had no measurable effect on oxidative phosphorylation. A concentration of 1.7 × 10−5 M 2,4-dinitrophenol had no appreciable effect on stimulation of respiration by ADP. ATPase activity was increased about 13% by dinitrophenol. It appears that high efficiency of oxidative phosphorylation is a true characteristic of the mitochondria used in this study.
Biochemical aspects of the interaction of ethanol with barbiturates
Authors: Trenholm H. Locksley , Maxwell William B. , Paul Charles J. , Wiberg G. Stuart , Coldwell Blake B.
Published: December 2009

When pentobarbital is added to a hepatic supernatant enzyme fraction which contains alcohol dehydrogenase from a rat, the rates of the enzyme-catalyzed oxidation of ethanol and reduction of acetaldehyde are increased. The pentobarbital enhancement of enzymatic activity which is dependent on pentobarbital concentration is still observed when the enzyme is purified by column chromatography on DEAE- and CM-Sephadex and ammonium sulfate precipitation. In in vitro studies where hepatic tissue slices were incubated with alcohol, pentobarbital inhibited the metabolism of alcohol and increased the acetaldehyde levels in the incubation mixture. The addition of 32.5 mM NAD resulted in a return of alcohol metabolism and acetaldehyde concentrations to control levels.
A heparin sulfamidase from mammalian lymphoid tissues
Authors: Dietrich Carl P.
Published: December 2009

A sulfamidase has been isolated from lymphoid tissues of rats, dogs, and man and purified by combined Sephadex gel filtration and gel electrophoresis. The enzyme which has an optimum pH of 5.0 is shown to catalyze the hydrolysis of a single N-linked sulfate residue from heparin and from hexa- and tetra-saccharides originating from the degradation of heparin by bacterial enzymes. The enzyme has no action upon N-sulfated disaccharides or glucosamine 2,6-disulfates or upon several sulfated mucopolysaccharides.The possible pathway for the complete desulfation of heparin, which occurs in vivo, is discussed on the basis of the properties of this sulfamidase.
The effect of temperature and of cofactor concentrations on the conversion of 4-14C-progesterone to corticosterone by rat adrenal preparations
Authors: Tsang Charles P. W. , Stachenko J.
Published: December 2009

When a Krebs–Ringer bicarbonate medium in which adrenal quarters have been preincubated (hereafter called PIM), is reincubated for 3 h in the presence of 4-14C-progesterone and a NADPH-generating system, it possesses the capacity of hydroxylating the progesterone molecule (5). When the PIM is prepared at 0 °C, its subsequent incubation at 37 °C enhances the conversion of progesterone to 21-hydroxy- and 11β-hydroxy-steroids 30-fold and fivefold, respectively, above those observed upon incubation of PIM prepared at 37 °C. Similarly when dilute homogenates (0.6 mg tissue per milliliter) are preincubated for 1 h at 21 °C prior to a 3-h incubation period in the presence of 4-14C-progesterone and proper cofactors, 21- and 11β-hydroxylations of progesterone are, respectively, six times and twice greater than when the preincubation temperature is 37 °C.It is concluded that: (i) 21- and 11β-hydroxylating systems are inactivated to a significant degree at 37 °C and that under these conditions the 21-hydroxylase system is much more labile than the 11β-hydroxylase system; and (ii) this difference in the degree of denaturation of these two steroid hydroxylase systems explains in part the accumulation of 11β-hydroxyprogesterone in the PIM as well as in homogenates.
Examination of the mineral composition of the micelle of milk by gel filtration
Authors: Boulet M. , Yang A. , Riel R. R.
Published: December 2009

When skim milk was passed through a column of Sephadex G-150 and eluted with distilled water, it separated into three peaks containing (I) "primary micelle", (II) "whey proteins", and (III) free electrolytes and other small molecules. "Primary micelle" which is composed of calcium caseinate and bound calcium phosphate was compared with whole micelle and colloidal phosphate-free micelle. The apparent lower calcium, magnesium, and phosphate contents, and absence of citrate in primary micelle were attributed to the removal of an adsorption layer from whole micelle. The qualitative and quantitative distribution of minerals in milk micelle is discussed and it appears that three zones could be distinguished: adsorbed double layer of ions, bound minerals, and casein counter-ions.
Aflatoxicok: structure of a new transformation product of aflatoxin B1
Authors: Detroy R. W. , Hesseltine C. W.
Published: December 2009

The incubation of aflatoxin B1 with a steroid-hydroxylating fungus yielded a cyclopentane ring reduction product with reduced biological activity.
Biosynthesis of angular furanocoumarins
Authors: Steck Warren , Brown Stewart A.
Published: December 2009

The biosynthesis of angular furanocoumarins from umbelliferone in Angelica archangelica and Heracleum lanatum has been shown by isotope studies to parallel that of linear furanocoumarins, via the dihydrofuranocoumarin columbianetin. Angelicin, the first angular furanocoumarin formed, is converted by hydroxylation and O-alkylation to a range of substituted angelicins. A detailed biosynthetic route to angular furanocoumarins, consistent with known stereochemistry, is proposed. By variations of this pathway, it is possible to account for the elaboration of pyranocoumarins, furanoquinoline alkaloids, furanochromones, and possibly other plant products which frequently co-occur with furanocoumarins.A separation of furanocoumarins by column absorption chromatography on silicic acid, and a synthesis of [2-14C]angelicin, are described.
Soluble esterases of human lung
Authors: Brebner J. , Kalow W.
Published: December 2009

The soluble esterases of human lung compared to liver and serum have been illustrated on starch gel. A common zone of esterases appears to exist in nearly all human tissues and may be physiologically important acetylesterases. The most marked difference between lung and liver esterases exists in the ones moving farthest towards the anode at pH 7.0. Lactic and malic dehydrogenase patterns in the two tissues are also quite different. The zone 2 esterases appear to have a molecular weight of approximately 150 000 and those of zones 1 and 3 may be in the range of 50 000 as shown by G-200 Sephadex column chromatography.