bluuebunny/crossref_metadata_2025 huggingface dataset:
THE LIVER PHOSPHOLIPIDS OF THE DEVELOPING CHICK EMBRYO
Authors: Noble R. C. , Moore J. H.
Published: December 2009

The concentrations and fatty acid compositions of the individual phospholipids in the livers of chick embryos on the 13th, 15th, 17th, 19th, and 21st days of incubation were compared with the concentrations and fatty acid compositions of the individual yolk phospholipids. The liver phospholipids contained higher proportions of phosphatidyl ethanolamine, phosphatidyl serine, and diphosphatidyl glycerol, and lower proportions of phosphatidyl choline, than did the yolk phospholipids. There was a constant increment (0.96 mg/day) of phosphatidyl choline in the liver during the period of incubation studied. The phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine of the liver generally contained higher concentrations of stearic, arachidonic, and docosahexaenoic acids, and lower concentrations of palmitic and oleic acids than did these phospholipid fractions in the yolk. The fatty acid compositions of the sphingomyelin in the liver and yolk were similar. The most pronounced changes in the fatty acid composition of the liver phospholipids during embryonic development were observed in the phosphatidyl choline fraction. These changes suggested that the α-palmitoyl-β-arachidonyl phosphatidyl choline in the liver was gradually replaced by α-stearoyl-β-linoleoyl phosphatidyl choline and a-stearoyl-β-docosahexaenoyl phosphatidyl choline.
EXCRETION OF PHOSPHOLIPIDS BY MEN ON FAT-FREE DIET
Authors: Ali S. S. , Kuksis A.
Published: December 2009

The fecal excretion of phospholipids was determined in three adult males during the last 4 days of three 8- to 16-day periods on a fat-free diet. The phospholipids were isolated and identified by column and thin-layer chromatography on silicic acid. The individual phospholipids were quantitatively estimated by gas chromatographic determination of the component fatty acids, using methyl heptadecanoate as internal standard. The range of total excretion of phospholipids was 64–100 mg/day per 100 g of dry feces. In all samples the major phospholipids were tentatively identified as phosphatidyl ethanolamine, phosphatidyl glycerol, and phosphatidyl inositol. Phosphatidyl ethanolamine made up 31–41% of the total excretion. All the phospholipids contained about the same fatty acids (C14–C27), but in somewhat varying proportions. Because of the occurrence of large amounts of the odd carbon number, among both branched and long chain fatty acids, which are not commonly associated with mammalian metabolism, the presence of phospholipids in the feces was attributed to bacterial synthesis.
COMPOSITION OF EPIPHYSEAL CARTILAGE: V. AMINO ACID AND AMINO SUGAR COMPOSITION OF EPIPHYSEAL CARTILAGE OF RACHITIC CHICKS; CHANGES EFFECTED BY VITAMIN D3
Authors: Cipera J. D.
Published: December 2009

Nineteen amino acids and two amino sugars were identified in the epiphyseal cartilage of rachitic chicks, and their levels estimated. Investigation of the effect of oral administration of vitamin D3on the levels of these amino acids and amino sugars showed that vitamin D3increased significantly the levels of galactosamine and decreased the levels of hydroxyproline and of glycine. The decrease in the levels of proline and cystine and increase in that of methionine were not statistically significant.
INTERRELATIONSHIP OF VITAMINS A AND C ON TISSUE UBIQUINONES AND STEROLS OF RATS AND GUINEA PIGS
Authors: Phillips W. E. J.
Published: December 2009

The effect of administration of ascorbic acid to normal or vitamin A-deficient rats was studied in relation to hepatic levels of ubiquinones and sterols. Similar studies were made on tissues from guinea pigs deficient in vitamin C, vitamin A, or both. Vitamin A deficiency increased the concentration of liver ubiquinones in the rat. Administration of ascorbate did not influence tissue levels of ubiquinones or sterols. Vitamin C deficiency increased the concentration of sterols but not of ubiquinones in the liver of the guinea pig. Vitamin A deficiency did not increase ubiquinones nor did a combined deficiency of vitamins A and C. A secondary effect of vitamin C deficiency in the vitamin A-deficient rat is not the cause of increased ubiquinone levels.
THE METABOLISM AND TOXICITY OF 2,3,6-TRIAMINOPYRIDINE, A METABOLITE OF PYRIDIUM
Authors: Burba John V.
Published: December 2009

2,3,6-Triaminopyridine (TAP), a metabolite of pyridium (DPP), is an unstable substance which decomposes readily in aqueous solution to yield colored oxidation products. No evidence was obtained that TAP was metabolized by direct ring hydroxylation, either in vivo (rabbit) or in vitro (rabbit-liver enzymes). The results indicated rather that the 2-amino group in the TAP molecule was replaced by a hydroxyl group during metabolism.A maximum of 15% of the administered dose of TAP was excreted unchanged, and from 1 to 25% was recovered as metabolites that could be acetylated by acetic anhydride to 2,3,6-triacetamidopyridine (TACP).The intraperitoneal LD50of TAP was found to be 76 mg/kg in mice, which is considerably less than that of its parent compound DPP. The increased toxicity of TAP may de due to TAP itself, its colored oxidation products, or a metabolite.
STUDY OF THE GLYCEROL KINASE OF MYCOBACTERIUM 607 BY A COLORIMETRIC ASSAY PROCEDURE
Authors: Pande S. V. , Parvin R. , Venkitasubramanian T. A.
Published: December 2009

A sensitive colorimetric method for glycerol kinase assay based on the estimation of phosphorus in L-α-glycerolphosphate is described. Conditions affecting reliability and limitations of the procedure are considered. The method was applicable for enzymatic glycerol estimation. Some of the properties of Mycobacterium 607 glycerol kinase were studied by the procedure described.
BIOSYNTHESIS OF FUSARIC ACID IN CULTURES OF FUSARIUM OXYSPORUM SCHLECHT
Authors: Dobson T. A. , Desaty D. , Brewer D. , Vining L. C.
Published: December 2009

The incorporation of radioactivity into fusaric acid from14C-labeled acetate and DL-aspartate was examined using two strains of Fusarium oxysporum. Acetate-1-14C labeled the carboxyl (C-7) group and alternate carbon atoms C-8 and C-10 of the n-butyl chain. The remaining two carbon atoms (C-9 and C-11) of the n-butyl chain were labeled by acetate-2-14C, which contributed only a small amount of radioactivity to C-7. Both precursors labeled the pyridine ring. Almost two-thirds of the label in fusaric acid produced from DL-aspartate-1-14C was in C-7 with most of the remainder in the pyridine ring; DL-aspartate-4-14C gave the reverse pattern. The proportion of radioactivity in C-7 decreased only slightly when contact time between precursor and culture was reduced. The distribution of label between C-7 and the pyridine ring was similar to that between C-1 and C-4 of protein aspartic acid isolated in the same experiment. Malonate-2-14C and glycerol-1,3-14C labeled fusaric acid to approximately the same extent as DL-aspartate-4-14C, but succinate-1,4-I4C was a poor precursor. The results are consistent with the biogenesis of fusaric acid from three units of acetate and one of aspartate. Yields of the metabolite from cultures grown on a modified Richards' medium were increased by supplements of sodium acetate, but not of aspartate.
STUDIES ON THE SYNTHESIS OF PLASMA GLYCOLIPOPROTEIN AND HEPATIC SUB-CELLULAR GLYCOPROTEIN IN EARLY CHOLINE DEFICIENCY
Authors: Mookerjea Sailen , Jeng David , Black Judith
Published: December 2009

Impairment of glycoprotein synthesis in trichloroacetic acid insoluble and in residual protein (d > 1.21) fractions of plasma in early choline deficiency has been confirmed. Plasma lipoproteins of d < 1.006, 1.006–1.063, and 1.063–1.21 are also rapidly labelled after intraperitoneal injection of glucosamine-1-14C. In general, there was no difference in specific radioactivity of plasma glycolipoproteins between choline-supplemented rats and rats deprived of choline for 2 days during 180 min of incorporation.Incorporation of glucosamine-1-14C into microsomal glycoprotein is significantly impaired in early choline deficiency. Further sub-microsomal fractionation produced evidence that the site of impairment of glycoprotein synthesis is in the smooth microsome portion. These studies suggest that a decreased synthesis of glycoprotein(s) in liver-microsome smooth membrane and in the plasma residual fraction (d > 1.21) may represent an impairment of 'lipoprotein precursor protein' synthesis in early choline deficiency. An inhibition of this limiting step would possibly impair the rate of plasma lipoprotein synthesis, leading to the development of fatty liver in choline deficiency.
STIMULATION OF LIPOGENESIS IN BIOTIN-DEFICIENT CHICKS BY DIETARY MALONIC ACID
Authors: Donaldson William E.
Published: December 2009

Experiments were conducted to examine possible mechanisms of dietary malonic acid stimulation of lipogenesis in biotin-deficient intact chicks. Both dietary fat and biotin deficiency reduced incorporation of acetate-14C into carcass fatty acids. Dietary malonic acid reduced acetate-14C incorporation into fatty acids by control chicks and did not restore incorporation to control levels in fat-fed and biotin-deficient chicks. The patterns of incorporation of succinate-14C and aspartate-14C were similar to the pattern of acetate-14C incorporation. Biotin deficiency did not reduce incorporation of orally administered malonate-14C into carcass fatty acids as compared with control incorporation. When unlabeled malonate was fed to biotin-deficient chicks, the percentage incorporation of malonate-14C into fatty acids was not reduced. The results suggest that dietary malonic acid is incorporated into carcass fatty acids in sufficient quantity to partially overcome inhibition of lipogenesis by biotin deficiency.
KINETICS OF NADH OXIDATION BY PIGEON-HEART MITOCHONDRIA
Authors: Griffith Thomas J. , Blanchaer M. C.
Published: December 2009

The oxidation of 1-10 μM NADH by pigeon-heart mitochondria prepared by the method of Chance and Hagihara was studied. In a medium consisting of 0.07 M sucrose, 0.23 M mannitol, 0.02 M Tris–HCl, 0.02 mM EDTA, all at pH 7.2, the concentration of NADH required for half maximal velocity was found to be approximately 5 μM. ATP and ADP appear to be competitive inhibitors of NADH oxidation. Application of Michaelis–Menten kinetics to the data yielded a Kiof 0.7 mM for both ATP and ADP. Some possible sites of inhibition by adenine nucleotides are discussed.
CONCERNING THE NATURE OF THE α- AND β-LYTIC PROTEASES OF SORANGIUM SP.
Authors: Whitaker D. R. , Roy C.
Published: December 2009

The α-lytic protease is readily inhibited by diisopropyl phosphorofluoridate (DFP) and the yield of serine phosphate from acid-hydrolyzed, DFP-inhibited enzyme indicates that DFP esterifies one serine residue of the enzyme. Acid digests of enzyme treated with isopropyl methylphosphonofluoridate-32P (sarin) show much the same electrophoretic patterns of 32P-labelled peptides as similar digests of sarin-treated trypsin and chymotrypsin; amino acid analyses and N-terminal amino acid analyses of peptides isolated from the digest confirm that the α-enzyme has the same sequence (Asp-Ser*-Gly-Gly) around the reactive serine residue as the pancreatic enzymes. At present, the α-enzyme is the only microbial "serine protease" which is known to have this sequence. It is also unique as a serine protease in that it has only one histidine residue.The β-lytic enzyme is not inhibited by DFP and shows no evidence of reactivity towards sarin. Its zinc atom can be removed by o-phenanthroline without loss of lytic activity. At present, it cannot be classed in any of the major groups of proteases.
THE TERMINAL GROUPS OF RIBONUCLEATE CHAINS IN EACH OF THE 16S AND 23S COMPONENTS OF ESCHERICHIA COLI RIBOSOMAL RNA
Authors: Nichols J. L. , Lane B. G.
Published: December 2009

Ribosomal ribonucleates from Escherichia coli have been resolved into 16S and 28S components by sucrose density-gradient centrifugation, and the chain termini in each of the 16S and 23S RNA components have been analyzed by hydrolysis with alkali. The principal 5′-linked end group of 16S RNA was found to be adenosine, and the principal 5′-linked end group of 23S RNA was found to be uridine. The principal 3′-linked end group of 16S RNA was also found to be adenosine, whereas the principal 3′-linked end group of 23S RNA was found to be guanosine. Quantitative estimates of chain length based on analyses for 5′-iinked terminals indicate that the mean chain length for 16S RNA is about 1.3 × 103nucleotide residues and the mean chain length for 23S RNA is about 2.1 × 103nucleotide residues.
FRACTIONATION AND COMPOSITION OF RIBONUCLEIC ACIDS FROM SCHIZOSACCHAROMYCES POMBE
Authors: Katona E.
Published: December 2009

A slightly modified variation of the Crestfield detergent method was used for isolation of the ribonucleic acids from Schizosaccharomyces pombe. A detailed description of the method is given. Nine fractions were prepared and analyzed for RNA, DNA, and protein content. These analytical results, together with yields, ε(P) values, and detailed results of the base composition of the fractions are presented.
HISTIDYL TRANSFER RIBONUCLEIC ACID SYNTHETASE FROM BAKERS' YEAST
Authors: Tigerstrom Margaret von , Tener G. M.
Published: December 2009

Histidyl-t-RNA synthetase has been purified 590-fold from toluene lysates of bakers' yeast (Saccharomyces cereviseae). Lysis with toluene inactivates most other synthetases. Further purification was achieved by precipitation with ammonium sulfate followed by chromatography on DEAE-cellulose and on calcium phosphate gel. Extensive loss of enzymic activity was noted during chromatography on DEAE-cellulose unless a hydrogen bonding substance, such as propylene glycol, was added to the eluting system. The purified enzyme was free of other aminoacyl-t-RNA synthetase activities except that for tryptophanyl-t-RNA and a trace of that for aspartyl-t-RNA. It was free of peptidase activity.
FREE RADICALS OF BIOLOGICAL INTEREST: I. ELECTRON SPIN RESONANCE SPECTRA OF TOBACCO SMOKE CONDENSATES
Authors: Forbes W. F. , Robinson J. C. , Wright G. F.
Published: December 2009

Smoke condensates, prepared from tobacco smoke, are shown to contain a variety of paramagnetically active centers. Some of these have lifetimes of a few seconds. Smoke condensates, when dissolved in sulfuric acid, give rise to at least two cation radical species. The more short-lived species may be the anthracene or an anthracene-type cation radical species and the more long-lived one may be a cation radical related to, but not identical with, the 3,4-benzpyrene cation radical.When 3,4-benzpyrene is heated to near its melting point, considerably more intense electron spin resonance (e.s.r.) spectra are obtained. The heated benzpyrene sample, when dissolved in sulfuric acid, also gives a more intense, but otherwise similar, spectrum than an unheated sample. These observations indicate that, on heating benzpyrene, additional free radicals are formed, and this may account for the relatively high carcinogenicity of tobacco smoke condensates.The e.s.r. spectrum of 3,4-benzpyrene in sulfuric acid undergoes an approximately 10-fold increase in signal intensity when similar amounts of 3,4-benzpyrene-6,7-quinone are added to the mixture. The latter compound on its own does not afford a detectable signal under these conditions. This indicates that the ability of known carcinogenic substances, such as 3,4-benzpyrene, to give rise to free-radical species can be appreciably affected by the molecular environment.
THE METABOLISM OF THE ERYTHROCYTE: XVII. MECHANISM OF INCORPORATION OF ADENINE INTO AND RESULTANT ELEVATION OF ATP AND ADP IN HUMAN ERYTHROCYTES
Authors: Manohar S. V. , Denstedt O. F. , Rubinstein D.
Published: December 2009

Human erythrocytes were incubated for 48 hours at 37 °C with adenine-8-14C and glucose. The incorporation of the adenine into nucleotides continued for 10–14 hours, most of the radioactivity being found in the ATP. Degradation of the nucleotides then commenced. In the absence of glucose, the breakdown of the newly synthesized ATP followed the pathway ATP → ADP → AMP → inosine → hypoxanthine. The breakdown of adenine-labeled ATP could be delayed beyond 10–14 hours if the incubation medium containing glucose was changed periodically. The specific activities of the adenine nucleotides during incorporation of adenine-8-14C were in the order AMP > ADP > ATP. Molar incorporation of pentose carbons from glucose-U-14C approached that of the adenine-8-14C, provided the pool of glycolytic intermediates had been labeled by preincubation with glucose-U-14C. The increase in the level of nucleotide-labile phosphate found experimentally corresponded to that calculated on the basis of adenine-8-14C incorporation into ATP and ADP. The level in labile phosphate was twice that found in fresh cells. It is concluded that adenine is incorporated via the pathway adenine → AMP → ADP → ATP, and that this may serve as a mechanism for raising the level of ATP in the erythrocyte at least twofold.
UTILIZATION OF CIRCULATING PRECURSORS FOR THE SYNTHESIS OF TESTOSTERONE BY HUMAN TESTIS IN VIVO
Authors: Lucis O. J. , Raheja M. C. , Millard O. , Morse W. I.
Published: December 2009

Infusion of 3H-labeled dehydroepiandrosterone together with 14C-labeled androst-4-ene-3,17-dione into the spermatic artery resulted in the formation of testosterone. 3H- and 14C-labeled testosterone was isolated from the spermatic venous blood and from the perfused testis. Under the experimental conditions used, androst-4-ene-3,17-dione yielded more testosterone than did dehydroepiandrosterone. Dehydroepiandrosterone also contributed towards the formation of androst-4-ene-3,17-dione.
CHANGES IN THE AQUEOUS AMMONIA SOLUBLE PROTEINS OF RAPESEED (BRASSICA NAPUS L.) DURING THE MATURING PERIOD
Authors: Finlayson A. J.
Published: December 2009

The changes in the amino acid composition of the two aqueous ammonia soluble proteins from rapeseed (Brassica napus L.) have been studied from the time that the seed contains a small amount of protein nitrogen until it is mature. Amino acid analyses and N-terminal amino acid analyses indicated that protein synthesis proceeds from the N-terminus of the protein towards the C-terminus. Although the results of the analyses cannot be interpreted unequivocally, they ruled out the possibility that the storage protein is synthesized by the condensation of similar polypeptide subunits.
UTILIZATION OF CHOLINE OR BETAINE FOR PHOSPHOLIPID SYNTHESIS IN AN AEROBIC MARINE MICROBE
Authors: Shieh H. S. , Spears D.
Published: December 2009

The same types of phospholipids were recovered from vegetative Achromobacter cholinophagum cells grown in a medium containing either choline or betaine. The principal phospholipid of this organism extractable in methanol–chloroform was phosphatidylethanolamine. Other unidentified phospholipid components were present in only trace amounts and no phosphatidylcholine could be detected. The utilization of [methyl-14C]choline as well as [methyl-14C]betaine for phospholipid synthesis in this culture has been demonstrated. Radioactivity from the phospholipids of Achromobacter cholinophagum is found in the ether-soluble portion as well as in the water-soluble portion after hydrolysis of phospholipids. Oxidation of [methyl-14C]choline to [methyl-14C]betaine was found to be catalyzed by the crude cell-free extracts.
OXIDATIVE PHOSPHORYLATION BY MUSCLE MITOCHONDRIA OF DYSTROPHIC MICE
Authors: Wrogemann Klaus , Blanchaer M. C.
Published: December 2009

Oxidative phosphorylation was studied in mitochondria isolated from the skeletal muscle of control and dystrophic mice of the Jackson Laboratory strain 129/Re, aged 32–104 days. The isolation procedure included a preliminary incubation of the muscle minced in a medium containing a proteinase (Nagarse) followed by gentle homogenization and differential centrifugation. Polarographic estimations in the presence and absence of adenosine diphosphate (ADP) indicated that the rate of oxygen uptake, ADP/0 ratio, respiratory control ratio, and phosphorylation rate were not significantly different in the mitochondria isolated from control and dystrophic mice. Bovine serum albumin increased the ADP/0 and respiratory control ratios, but the values for the control and dystrophic preparations again did not differ significantly in the presence of albumin.
SOLUBLE NADP-LINKED DIHYDROOROTATE DEHYDROGENASE FROM A PSEUDOMONAD
Authors: Kerr Carolyn T. , Miller Richard W.
Published: December 2009

Soluble dihydroorotate dehydrogenase was purified from aerobic soil organisms of the genus Pseudomonas after growth on orotate medium. The enzyme was purified by ammonium sulfate fractionation, chromatography on DEAE cellulose, precipitation by protamine sulfate, and adsorption on calcium phosphate gel. Chemical analysis of the purified material revealed the presence of labile sulfide in amounts roughly equivalent to non-heme iron.Catalytic properties of the enzyme in several substrate systems were studied and relative activities are reported. It was necessary to activate the enzyme with sulfhydryl compounds to obtain maximal activity in the reduction of orotate by NADPH or oxidation of dihydroorotate by molecular oxygen. Sodium ethylenediaminetetraacetate did not stimulate activity in contrast to results obtained previously with the enzyme isolated from Zymobacterium oroticum.Initial rates of oxidation of both reduced substrates by oxygen reflected similar turnover numbers based on bound flavin. The enzyme purified from aerobic soil organisms shows high specificity for NADPH. The low oxidase activity for this substrate and the large effects of oxygen concentration on reactions involving molecular oxygen have an undetermined mechanistic basis. These results represent the major observed differences between the enzyme purified from anaerobic and aerobic microorganisms.Both horse heart cytochrome c and a bacterial cytochrome c served as oxidizing agents for sodium dihydroorotate. The bacterial cytochrome was present in large quantities in the pseudomonad which was used as a source of inducible dihydroorotate dehydrogenase. This reaction required the presence of an intermediate electron carrier such as molecular oxygen or the ferrocyanide–ferricyanide couple.
THE EFFECT OF ETHER, PENTOBARBITAL, AND DECAPITATION ON VARIOUS METABOLITES OF RAT SKELETAL MUSCLE
Authors: Marquez-Julio Ana , French I. W.
Published: December 2009

The concentrations of creatine phosphate, ATP, ADP, AMP, lactate, pyruvate, hexose monophosphate, and glycogen were examined in skeletal muscle obtained from decapitated rats, or animals anesthetized with ether or pentobarbital.The concentrations of ATP, creatine phosphate, and glycogen were highest in muscles from pentobarbital-treated rats, whereas those of AMP, ADP, lactate, and pyruvate were the lowest in these animals. The data suggest that changes in the concentration of metabolites in skeletal muscle were less when the tissue was isolated under pentobarbital anesthesia than when it was isolated from decapitated or ether-anesthetized rats.
CHANGES PRODUCED BY PROTEIN MALNUTRITION IN THE PROTEOLYTIC ACTIVITY OF HUMAN LIVER
Authors: Umaña Roberto
Published: December 2009

The acid proteolytic activity in the livers of children who died of kwashiorkor or marasmus was compared with that of the livers of children who died of non-nutritional causes. The malnourished children had higher proteolytic activities than normal. There was no difference in the specific activity (expressed in units per milligram of nitrogen) between the livers of children with marasmus and those of children with kwashiorkor. These results are in good agreement with previous studies in rats given protein-deficient diets.
VARIATION WITH AGE OF THE ENZYMES OF THE UREA CYCLE AND ASPARTATE TRANSCARBAMYLASE IN RAT LIVER
Authors: Charbonneau R. , Roberge A. , Berlinguet L.
Published: December 2009

The activities of aspartate transcarbamylase and of five enzymes involved in the urea cycle were determined in the liver of rats from the embryonic state to adulthood. Aspartate transcarbamylase activity is very high in the embryo and at birth. It remains high until the rat reaches a body weight of 50 g, after which there is a rapid decrease which levels off to a plateau at adulthood. The enzymatic activities of carbamyl phosphate synthetase, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinase, and arginase are very low at the embryonic stage. The activity of these enzymes increases gradually with age until a plateau is reached, except for argininosuccinase which also increases in young animals but decreases in adult life. Of these enzymes, argininosuccinate synthetase always has the lowest activity and seems to be the limiting factor in the synthesis of urea. These results indicate that the biosynthesis of pyrimidines and urea vary inversely at different ages that correspond to different metabolic activities of the animals. Thus, an inverse relation is established between the two pathways from carbamyl phosphate, leading to protein biosynthesis (formation of RNA from orotic acid) and to protein catabolism (formation of urea).
REDUCTION AND ALKYLATION OF HUMAN PLASMA OROSOMUCOID IN AQUEOUS SOLUTION AND IN 8 MUREA: A PHYSICOCHEMICAL AND IMMUNOCHEMICAL STUDY: HUMAN OROSOMUCOID: REDUCTION AND ALKYLATION
Authors: Krotoski W. A. , Weimer H. E.
Published: December 2009

Highly purified orosomucoid (α1-acid glycoprotein) was exposed to mercaptoethanol, iodoacetamide and 8 M urea, in various combinations. The derivatives were examined by agar-gel electrophoresis, by acrylamide-gel "disc" electrophoresis (employing an improved method), by immunodiffusion techniques, and by quantitative immunochemical methods.The results indicated an —S—S— dependent tertiary structure for the polypeptide backbone, but one which could not be separated into subunits by the methods employed. The mechanisms of reduction and alkylation of the glycoprotein are discussed, and several alternate structural models for the polypeptide moiety are presented.
BEHAVIOR OF α-SUBSTITUTED CYSTINES IN A CYSTATHIONASE SYSTEM AND IN A PYRIDOXAL PHOSPHATE MODEL SYSTEM
Authors: Thibert R. J. , Diederich J. F. G. , Kosicki G. W.
Published: December 2009

The behavior of several new α-substituted cystines synthesized in this laboratory (α-methyl-, α-ethyl-, α-n-propyl-, α -n-butyl-, α-isopropyl-, and α-phenyl-DL-cystine) was studied in a cystathionase system and in a pyridoxal phosphate model system.The substituted cystines were neither cleaved by cystathionase nor were they degraded in the model system consisting of pyridoxal phosphate with or without cupric ions. Under the latter conditions, L-cystine reacted even in the absence of added metal. Copper ions, however, increased the rate of degradation of the amino acid. The α-hydrogen atom was apparently required for reactivity.The enzymatic system with cystathionase, isolated from rat liver and purified to some extent, was inhibited competitively by L-cystine and the substituted sulfur amino acids. Inhibition by the natural substrate, L-cystine, was greatest.In the non-enzymatic system, the substituted amino acids formed reactive Schiff bases whose absorption spectra were determined. The rates of formation of these addition compounds were followed spectrophotometrically.
ANTIGENICITY OF 5-HYDROXYINDOLE-3-ACETIC ACID, A DERIVATIVE OF SEROTONIN: II. ANTIBODIES SPECIFIC TO 5-HYDROXYINDOLEACETIC ACID
Authors: Ranadive N. S. , Sehon A. H.
Published: December 2009

Precipitating antibodies specific to 5-hydroxyindoIeacetic acid (5HIAA) were produced in rabbits by immunization with conjugates of bovine γ-globulins containing 28–30 residues of 5HIAA covalently coupled per globulin molecule. The specificity of anti-5HIAA antibodies was demonstrated by immunodiffusion and by hapten inhibition of precipitation by appropriate univalent derivatives of 5HIAA, viz. 5-hydroxyindole-3-acetylaminocaproic acid and 5-hydroxytryptamine (5HT).The anti-5HIAA antibodies produced in rabbits had the capacity of neutralizing the effect of exogeneous 5HT on capillary permeability in mice, and were capable of inhibiting only partially the passive cutaneous reactions in mice.
PURIFICATION AND PROPERTIES OF THE INDUCIBLE CHOLINESTERASE OF PSEUDOMONAS FLUORESCENS (GOLDSTEIN)
Authors: Laing Allan C. , Miller Helen R. , Bricknell Kenneth S.
Published: December 2009

The inducible cholinesterase produced by the Goldstein strain of Pseudomonas fluorescens was purified to a state of electrophoretic homogeneity. The enzyme, which resembles an acetylcholinesterase in its substrate specificity, has a high affinity for acetylcholine and propionylcholine. The estimated values of Kmat pH 7.4 and 37 °C are 1.4 × 10−5 M for acetylcholine and 2.0 × 10−5 M for propionylcholine. The bacterial cholinesterase reacts very slowly with tetraethyl pyrophosphate (TEPP) and diisopropyl phosphorofluoridate (DFP) but comparatively rapidly with ethyl N,N-dimethylphosphoramidocyanidate (Tabun). Bimolecular rate constants range from 7.7 mol−1min−1for TEPP to 7.4 × 104 mol−1min−1for Tabun. The reactions of the cholinesterase depend upon the ionic state of groups in the enzyme whose pKavalues are in the same range as those reported for other esterases. The results suggest that the enzyme may be similar in structure to other cholinesterases, and that both histidine and serine may be involved in its activities.
LIPIDS OF SUBCELLULAR PARTICLES FROM BOVINE HEART MUSCLE: II. FATTY ACIDS OF PHOSPHOLIPIDS
Authors: Nazir Darius J. , Alcaraz Aurora P. , Nair Padmanabhan P.
Published: December 2009

The fatty acid composition of six phospholipid classes, cardiolipin, cephalin, lysocephalin, lecithin, sphingomyelin, and lysolecithin from various subcellular fractions of beef heart, was studied. With the exception of the microsomal fraction, all other classes revealed phospholipid fractions having uniform fatty acid composition. The microsomes, which form a major phospholipid compartment in the heart muscle, exhibited relatively higher levels of total polyenes, which is a distinct attribute of microsomal phospholipids.
L'UTILISATION DE L'ACIDE VALERIQUE-1-14C ET LA SYNTHESE DE LIPIDES MARQUES PAR LES BACTERIES CELLULOLYTIQUES DU RUMEN IN VITRO
Authors: Hidiroglou M. , Lepage M.
Published: December 2009

not available
DDT-INDUCED METABOLIC CHANGES IN RAT LIVER
Authors: Sánchez Emilio
Published: December 2009

Administration of DDT to rats resulted in an increase in the rate of incorporation of DL-leucine-1-14C into proteins by a liver cell-free system. This effect was paralleled by an increase in the activity of microsomal DDT-metabolizing enzymes and in total liver protein, as well as by increased synthesis of RNA. The level of total glutathione in liver and blood was not modified, but the amount of the oxidized form was increased at the expense of the reduced form. Phenobarbital or hydrocortisone also increased the levels of microsomal DDT-metabolizing enzymes but their combination with DDT produced a relative inhibition. The role of DDT as an enzyme inducer and the possibility that changes in RNA correspond to increased synthesis of messenger RNA are discussed. These results confirm and extend previous ones obtained in this laboratory.
DEGRADATION OF AROMATIC AMINO ACIDS BY FUNGI: II. PURIFICATION AND PROPERTIES OF PHENYLALANINE AMMONIA-LYASE FROM USTILAGO HORDEI
Authors: Rao P. V. Subba , Moore K. , Towers G. H. N.
Published: December 2009

Phenylalanine ammonia-lyase (EC 4.3.1.5) isolated from the cells of Ustilago hordei was purified 128-fold. The purified enzyme catalyzed the stoichiometric deamination of L-phenylalanine to trans-cinnamic acid. The optimum pH was about 8.8 and the Michaelis constant for L-phenylalanine was 0.45 mM. The enzyme preparations also catalyzed the deamination of DL-m-fluorophenylalanine, DL-p-fluorophenylalanine, and DL-m-hydroxyphenylalanine, although there was greater affinity of L-phenylalanine. The enzymic product from m-hydroxyphenylalanine was isolated and characterized as m-coumaric acid. No deamination of tyrosine could be demonstrated either with crude or purified preparations. Apparently there was no cofactor or metal ion requirement for the reaction. Sulfhydryl inhibitors like p-chloromercuribenzoate and N-ethylmaleimide partially inhibited the reaction in the presence of ethylenediaminetetracetate. The high susceptibility of the enzyme to inactivation by heavy metal ions like Ag+, Hg+, and Cd++also suggest the involvement of sulfhydryl groups in the reaction. Several compounds structurally related to phenylalanine were inhibitory, trans-Cinnamic acid exerted strong product inhibition. Reversibility of the reaction was demonstrated.
THE EFFECT OF 4-HYDROXY-3,5-DIIODOBENZONITRILE (IOXYNIL) ON RESPIRATORY ELECTRON TRANSPORT IN VICIA FABA L.
Authors: Paton David , Smith John E.
Published: December 2009

Oxygen reduction by mitochondria prepared from young bean root tips is inhibited by the herbicide ioxynil. This inhibition can be reversed by menadione (vitamin K3) and by ubiquinol but not by ubiquinone. Ioxynil is thought to inhibit ubiquinone reduction when succinate or NADH is supplied as substrate to isolated mitochondria. The addition of bovine serum albumin to mitochondrial preparations appears to reduce the inhibitory effects of ioxynil.
THE BIOSYNTHETIC PATHWAY FROM CAFFEIC ACID TO SCOPOLIN IN TOBACCO LEAVES
Authors: Steck Warren
Published: December 2009

The incorporation of a number of compounds into scopoletin glucoside was measured with 14C. A biosynthetic pathway from phenylalanine involving caffeic acid, ferulic acid, and glucosidoferulic acid seems to best fit the observations. An alternate route involving esculetin and cichoriin as intermediates was shown not to function in tobacco leaves. Preparations of [3-14C]scopoletin, [3-14C]esculetin, and [2-14C]4′-glucosidocaffeic acid are described.
A SIMPLIFIED APPROACH TO THE USE OF DETERMINANTS IN THE CALCULATION OF THE RATE EQUATION FOR A COMPLEX ENZYME SYSTEM
Authors: Hurst R. O.
Published: December 2009

A standardized method of treating the analysis of enzymic reaction mechanisms by means of determinant expressions is given. The fully expanded polynomial expressions for systems of order three, four, and five are presented and their use described. Application of the method to the analysis of the effect of dead-end inhibitors on enzymic reactions is discussed and the inhibitor constants are evaluated in terms of the rate constants involved in the inhibition mechanism. Examples are given to demonstrate the contribution that inhibitor studies may make in the search for information concerning the nature of the enzymic reaction mechanism, in the calculation of the rate constants, and in the estimation of the proportion of the enzyme distributed between the different enzyme forms involved in the reaction.
Metabolism of p-aminobenzoic acid by a chloramphenicol-producing Streptomyces sp.
Authors: Siddiqueullah M. , McGrath R. , Vining L. C. , Sala F. , Westlake D. W. S.
Published: December 2009

Small amounts of p-nitrobenzyl alcohol were isolated from chloramphenicol fermentations with Streptomyces sp. 3022a. Cultures supplemented with p-aminobenzoic acid also yielded p-nitrobenzoic acid. Radioactivity from p-aminobenzoic-ring-14C acid was incorporated more efficiently into p-nitrobenzoic acid than into the alcohol; relatively little appeared in chloramphenicol. A large proportion of the radioactivity was found in the mycelium, from which bound forms of labeled p-nitrobenzoic acid and p-nitrobenzyl alcohol were obtained. The results suggest that p-aminobenzoic acid is oxidized to p-nitrobenzoic acid as a covalent complex, and that part of the p-nitrobenzoic acid produced is converted further to p-nitrobenzyl alcohol.
Glucosidases and exo-glucanases
Authors: Reese Elwyn T. , Maguire Anne H. , Parrish Frederick W.
Published: December 2009

A comparison was made of exo-α-glucanases with α-glucosidases, and of exo-β1 → 3-glucanases with β-glucosidases to establish criteria for their characterization. Dimers, trimers, and tetramers of glucose are substrates for both exo-glucanases and glucosidases. Exo-glucanases act more rapidly on the longer oligomers, glucosidases on the shorter. Exo-glucanases act with inversion of configuration, glucosidases with retention. Other differences are found in transfer activity, in degree of specificity, and in susceptibility to various inhibitors.
Synthesis of propylene glycol phospholipids: analogues of α-lecithins and α-cephalins
Authors: Baer Erich , Duke Angus J. , Buchnea Dmytro
Published: December 2009

The synthesis of phospholipids derived from propylene glycol, structurally the least complex polyhydric alcohol to possess an asymmetric center, is described. Representatives of two types of propylene glycol phospholipids were prepared. They are analogues of α-(dipalmitoyl)lecithin and α-(dipalmitoyl)cephalin, and were obtained from D-propylene glycol via the following two series of intermediates: (A) α-trityl D-propylene glycol (I) → α-trityl, β-palmitoyl D-propylene glycol (II) → β-palmitoyl D-propylene glycol (III) → β-palmitoyl D-propylene glycol-α-(phenyl)phosphorylcholine chloride (IV) → β-palmitoyl D-propylene glycol-α-phosphorylcholine (V); and (B) I → II → III → β-palmitoyl D-propylene glycol-α-(phenyl)phosphoryl-N-carbobenzoxyethanolamine (VI) → β-palmitoyl D-propylene glycol-α-phosphorylethanolamine (VII). The palmitoyl D-propylene glycol-α-phosphorylcholine, a highly water-soluble compound, possesses strong hemolytic activity, whereas the palmitoyl D-propylene glycol-α-phosphorylethanolamine has no hemolytic properties whatsoever.
Liver glucokinase of the biotin deficient rat
Authors: Dakshinamurti K. , Cheah-Tan C.
Published: December 2009

The physiological role of liver ATP: D-glucose-6-phosphotransferase with a high Km for glucose is now well recognized. The activity of this enzyme (glucokinase) is greatly reduced in the liver of the starving or diabetic animal. Our results show that glucokinase is reduced by 40–45% in the biotin deficient rat liver. The specific activity of this enzyme decreases during fasting in both control and deficient rat livers. The extent of the increase in glucokinase activity of the deficient rats following refeeding is considerably lower than in control animals. When biotin deficient rats are given either biotin or insulin or both, the liver glucokinase activity is restored to the control level within 24 h.
The in vitro O2′-methylation of RNA in the ribonucleoprotein precursor-particles from a Relaxed mutant of Escherichia coli
Authors: Nichols J. L. , Lane B. G.
Published: December 2009

Ribonucleoprotein "precursor-particles" were isolated from a methionine auxotroph of E. coli (RCrelaxed), which had been cultured under conditions of methionine deprivation. Following incubation of the "particles" in vitro with [methyl-14C]-S-adenosyl methionine, the ribonucleates were extracted from the particles, and precipitated from aqueous 2 M sodium chloride solution at 0°, before analysis for the incorporation of O2′-[methyl-14C]-substituents into the RNA. It was found that two of the four principal alkali-stable dinucleotides, known to be present in alkali hydrolysates of E. coli rRNA, contained O2′-[methyl-14C]-substituents: O2′Me-GpGp and O2′Me-CpCp, whereas the two remaining dinucleotides, N4,O2′diMe-CpCp and O2′Me-UpGp, did not contain significant radioactivity. It has been concluded that highly specific enzymic O2′-methylation of E. coli RNA can occur subsequent to polynucleotide synthesis. Allied studies are reported concerning the characterization of N4,O2′-[dimethyl-14C]-cytidine 5′-phosphate that was recovered from whole snake venom hydrolysates of E. coli rRNA, which had been labeled in vivo with [methyl-14C].
Effect of thyroid hormones on metabolism. II. The effect of adrenalectomy or hypophysectomy on responses of rat liver enzyme activity to L-thyroxine injection
Authors: Freedland R. A. , Avery E. H. , Taylor A. R.
Published: December 2009

Many enzyme activities which were increased by hydrocortisone were decreased by adrenalectomy. This effect was more apparent with enzymes related to amino acid metabolism than those related to carbohydrate metabolism. The latter, although significantly increased by hydrocortisone, did not show marked decreases after adrenalectomy. Hypophysectomy decreased the activities of many enzyme systems associated with carbohydrate metabolism more drastically than did adrenalectomy. The results with the enzymes related to amino acid metabolism were not as clear. Several of these were decreased to a greater degree after hypophysectomy than after adrenalectomy. In contrast, several enzymes were also increased above the control values after hypophysectomy. Adrenalectomy was particularly efficient in decreasing the activities of several transaminases, and hypophysectomy had a marked effect upon decreasing TPN+-linked enzyme systems.The response of several enzymes to L-thyroxine injections was decreased in magnitude or eliminated after adrenalectomy. This was particularly true for enzymes associated with carbohydrate metabolism. Several enzymes increased by L-thyroxine in intact animals were actually decreased in adrenalectomized rats after this treatment. This was particularly true for serine dehydrase and glutamic–pyruvic transaminase. These results are strongly suggestive of a thyroxine–adrenal interaction in the intact animal. Hypophysectomy had a similar effect on enzyme responses to L-thyroxine, with the exception of glutaminase. Therefore, many of the effects of hypophysectomy may actually be related to a lack of adrenal function. It was observed that the removal of the adrenal had similar effects on responses of enzyme activity after thyroxine treatment, as did pituitary removal. Certain of the enzymes were decreased to a greater extent by hypophysectomy, and others were actually increased in activity after removal of the pituitary. It therefore appears that in many enzyme systems there is a complete requirement for the pituitary and (or) adrenals for a L-thyroxine effect on enzyme activity. In other enzyme systems the dependence appears to occur but does not appear to be complete.
Agents affecting lipid metabolism. XXXII. Effect of a liver mitochondrial extract on cholesterol synthesis in the rat
Authors: Cayen M. N. , Hill P. , Dvornik D.
Published: December 2009

A lyophilized extract was prepared from liver mitochondria of rabbits starved for 24 h. Rats were fed single oral (1–4 g/kg body weight) and intraperitoneal (1.5 g/kg) doses of the crude extract. After 3 h, the livers of one group were removed and 2-14C-acetate incorporation into cholesterol was measured. In the second group, rats received an interperitoneal dose of 2-14C-acetate 1 h after administration of the mitochondrial extract; animals were sacrificed 2 h later and the incorporation into hepatic cholesterol was measured. Under these experimental conditions, administration of the mitochondrial extract did not decrease the incorporation of 2-14C-acetate into liver cholesterol.
Acid-soluble metabolites of adenine-2-14C and adenine-8-14C in 2,6-diaminopurine-sensitive and 2,6-diaminopurine-resistant L strain mouse cells
Authors: Blair D. G. R.
Published: December 2009

The acid-soluble metabolites of adenine-2-14C and adenine-8-14C formed by 2,6-diaminopurine-sensitive and 2,6-diaminopurine-resistant L strain mouse cells have been separated by ion-exchange resin and paper chromatography. At least 20 acid-soluble metabolites were formed in 2,6-diaminopurine-sensitive cells. Significant, but much smaller amounts of some of these metabolites were also synthesized in 2,6-diaminopurine-resistant cells.
Variability in cell-specific and common histones of avian erythrocytes
Authors: Neelin J. M.
Published: December 2009

Histones extracted with acid from duck, goose, turkey, pigeon, and gull erythrocyte nuclei contained a major component, electrophoretically homologous with the serine-rich histone of chicken erythrocytes. This characteristic component was lacking or adventitious in duck, goose, and turkey spleens and marrows (as well as chicken tissues), but prominent in erythrocytes from birds under various physiological conditions, in reticulocytes as well as mature erythrocytes, and in nuclei prepared under various circumstances of cytolysis.Other electrophoretic components of erythrocytes and tissues, some apparently tissue-specific, were more variable in occurrence. Electrophoretic zones corresponding to arginine-rich histones, which had previously been considered as specifically absent from chicken erythrocytes, were in fact especially refractory to acid extraction from red cell nuclei. Furthermore, variability in electrophoretic pattern of these zones was attributed in part to conformational changes, which were sensitive to β-mercaptoethanol and to urea.
Ubiquinone, vitamin A, and sterol levels in liver of neonatal pigs
Authors: Phillips W. E. J. , Brien R. L.
Published: December 2009

In the livers of newborn pigs, the concentration of non-saponifiable constituents was similar to that in the livers of mature pigs but the concentration of ubiquinones was double. Ubiquinone concentration increased for about the first 2 weeks, then markedly decreased during the third week. Liver vitamin A increased rapidly during the first week and more slowly during the next 2 weeks. The concentration of sterols in the liver at birth was slightly higher than for mature pigs and remained relatively constant for 3 weeks.
Binding of testosterone and estradiol in plasma
Authors: Murphy Beverley E. P.
Published: December 2009

It has been shown that the two major active sex hormones, estradiol and testosterone, are bound with high affinity to a common site (or sites) on plasma globulin. The level of this protein is elevated slightly in portal cirrhosis and greatly in the later months of pregnancy. The high specificity and affinity of this protein for the sex hormones has enabled it to be used to provide a sensitive radioassay for their determination in small amounts of body fluids.
Relative reactivities of primary alcohols as substrates of liver alcohol dehydrogenase
Authors: Tsai C. S.
Published: December 2009

To obtain information concerning the general structural requirement of alcohols as substrates of liver alcohol dehydrogenase, the kinetics of the enzymic oxidation of primary alcohols were studied. All the active substrates possess hydrophobic side groups. Introduction of polar groups renders alcohols inactive or inhibitory. To correlate reactivities of primary alcohols as substrates with the nature of their side groups, their relative reactivities are expressed in terms of kinetic coefficients which were solved from the rate equation by successive graphical analysis. Based on kinetic results, the relative reactivities of primary alcohols as substrates of liver alcohol dehydrogenase are discussed in relation to the hydrophobic interaction and the electronic effect of their side groups.
The action of some enzymes on homolysine derivatives
Authors: Seely John H. , Benoiton Leo
Published: December 2009

DL-Homolysine was resistant to the action of lysine decarboxylase from Bacterium cadaveris, but was oxidized by L-amino acid oxidase from Crotalus adamanteus. ε-N-Acetyl-DL-homolysine was not hydrolyzed by ε-lysine acylase from hog kidney, but was hydrolyzed by a chicken kidney enzyme preparation. Hog kidney acylase showed slight activity towards α-N,ζ-N-dichloroacetyl- and α-N-chloroacetyl-ζ-N-carbobenzoxy-DL-homolysine. DL-Homolysine ethyl ester was hydrolyzed by trypsin at a rate one-eighth of that for lysine ethyl ester.
Increased sensitivity in fluorometric determinations of nicotinamide nucleotide coenzymes
Authors: Green W. G. E. , Israelstam G. F.
Published: December 2009

The fluorescence of NAD+ and of NADH in alkaline solution was increased by the addition of ethanol to the reaction mixture. Solutions of 4.5 × 10−10 μmole of coenzyme in 0.625 ml, 8 N in NaOH, were treated with 3.0 ml of aqueous ethanol solutions of various concentrations. A 50% (v/v) solution was most effective, increasing the fluorescence intensity 2.3–2.7 times that of water-treated preparations.