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991 The isolation is described of pure cultures of three non-methane-utilizing methylotrophic bacteria which, together with the previously described Bacillus PM6, have a very limited range of growth substrates; these organisms are designated "restricted facultative' methylotrophs. Two of these isolates, W6A and W3A1, g... |
992 Stearic acid desaturase activity was assayed in preparations from perigenital adipose tissue and liver from lean and genetically obese female mice (ob/ob). The total activity in the perigenital adipose tissue from obese mice was threefold greater than in the tissue from lean mice, but per g of adipose tissue the ac... |
993 195582 Noradrenaline stimulated the incorporation of oleate into choline glycerophospholipids of guinea-pig brain synaptic membranes incubated in sodium phosphate buffer. In the presence of 1 mm-NaF, noradrenaline stimulated the incorporation of oleate into the choline glycerophospholipids, phosphatidylinositol, et... |
994 The binding of Mg2+ to the wall teichoic acid of Lactobacillus buchneri N.C.I.B. 8007 was measured by equilibrium dialysis at controlled ionic concentration and pH. In an aqueous solution containing 10mM-NaCl at pH 5.0 one Mg2+ ion was bound for every two phosphate groups of the teichoic acid, with an apparent asso... |
995 1. To identify the functional groups that are involved in the conversion of beta-glycerophosphate by alkaline phosphatase (EC 3.1.3.1) from pig kidney, the kinetics of alkaline phosphatase were investigated in the pH range 6.6-10.3 at substrate concentrations of 3 muM-30 mM. From the plots of log VH+ against pH and... |
996 The pH-dependence of the kinetic parameters for the hydrolysis of the beta-lactam ring by beta-lactamase I (penicillinase, EC 3.5.2.6) was studied. Benzylpenicillin and ampicillin (6-[D(-)-alpha-aminophenylacetamido]penicillanic acid) were used. Both kcat. and kcat./Km for both substrates gave bell-shaped plots of ... |
997 An enzyme system from Datura innoxia roots oxidizing formylphenylacetic acid ethyl ester was purified 38-fold by conventional methods such as (NH4)2SO4 fractionation, negative adsorption on alumina Cy gel and chromatography on DEAE-cellulose. The purified enzyme was shown to catalyse the stoicheiometric oxidation o... |
998 1. 2-Oxoaldehyde dehydrogenase was purified from sheep liver and gave one band on polyacrylamide-gel electrophoresis. 2. The enzyme was completely dependent for its activity on the presence of Tris or one of a number of related amines, all of general structure: (See article). When more than one R group was hydrogen... |
1000 The NADP-specific glutamate dehydrogenase of Neurospora crassa was digested with trypsin, and peptides accounting for 441 out of the 452 residues of the polypeptide chain were isolated and substantially sequenced. Additional experimental detail has been deposited as Supplementary Publication SUP 50052 (11 pages) w... |
1001 The extracellular proteinase of Staphylococcus aureus strain V8 was used to digest the NADP-specific glutamate dehydrogenase of Neurospora crassa. Of 35 non-overlapping peptides expected from the glutamate content of the polypeptide chain, 29 were isolated and substantially sequenced. The sequences obtained were v... |
1002 Peptic and chymotryptic peptides were isolated form the NADP-specific glutamate dehydrogenase of Neurospora crassa and substantially sequenced. Out of 452 residues in the polypeptide chain, 265 were recovered in the peptic and 427 in the chymotryptic peptides. Together with the tryptic peptides [Wootton, J. C., Ta... |
1003 1. The activities of citrate synthase and NAD+-linked and NADP+-linked isocitrate dehydrogenases were measured in nervous tissue from different animals in an attempt to provide more information about the citric acid cycle in this tissue. In higher animals the activities of citrate synthase are greater than the sum... |
1004 1. Activity of 5-aminolaevulinate synthetase was measured in the midgut and other tissues of the last larval instar of the southern armyworm (Spodoptera eridania Cramer, formerly Prodenia eridania Cramer). 2. Optimum conditions for measuring the activity were established with respect to all variables involved and ... |
1126 Over several years sera were collected from 14 heterophil-positive students or patients who did not fulfill minimal hematologic criteria for infectious mononucleosis (I.M.) The specificity of these heterophil reactions for I.M. was investigated by determining antibodies to Epstein-Barr virus-determined antigens, i... |
1132 1 The concentrations of noradrenaline and adrenaline in various organs, arterial plasma and venous outflow from isolated hearts of adult chickens have been determined. 2 The relative adrenaline concentrations (percentage of the sum of noradrenaline and adrenaline) in the heart (33%), spleen (16%) and brain (26%) w... |
1133 1 The antiarrhythmic, haemodynamic and metabolic effects of a new amino steroid, ORG6001, have been investigated in experimental acute myocardial infarction in anaesthetized greyhounds. 2 ORG6001 administered either intravenously (2-10 mg/kg) or orally (50 mg/kg) significantly reduced the incidence of ventricular ... |
1246 Horse liver alcohol dehydrogenase was reacted with glyoxal at different pH values ranging from 6.0 to 9.0. At pH 9.0 the enzyme undergoes a rapid activation over the first minutes of reaction, followed by a decline of activity, which reaches 10% of that of the native enzyme. Chemical analysis of the inactivated en... |
1247 In delta-chymotrypsin the reactivity of methionine-192 towards p-nitrophenacyl bromide is strongly reduced when the alpha-amino group of isoleucine-16 has been acetylated. Since acetylation of isoleucine-16 brings delta-chymotrypsin to a conformation similar to its alkaline one this suggests that methionine-192 sh... |
1248 The kinetic mechanism of action of octopine dehydrogenase was investigated. This enzyme catalyses the reversible dehydrogenation of D-octopine to L-arginine and pyruvate, in the presence of nicotinamide-adenine dinucleotide. Initial velocity and product inhibition studies were carried out in both directions. Most ... |
1249 1. The steady-state kinetics of the interconversion of CO2 and HCO3 catalyzed by human carbonic anhydrase C was studied using 1H2O and 2H2O as solvents. The pH-independent parts of the parameters k(cat) and Km are 3-4 times larger in 1H2O than in 2H2O for both directions of the reaction, while the ratios k(cat)/Km... |
1250 30314843 Two isoenzymes of an NADP+ -dependent cinnamyl alcohol dehydrogenase and an NAD+ - dependent aliphatic alcohol dehydrogenase were extracted from cell suspension cultures of soybean (Glycine max L., var. Mandarin) which form lignin during growth. These enzymes could be separated from each other by chromato... |
1251 The presence of activators(AMP and sulphate) or inhibitors(acetyl-CoA) has no influence on the Hill coefficient of the S-shaped [pyruvate]--velocity curve of either the pyruvate-NAD+ overall reaction(h equals 2.5) or that of the pyruvate-K3Fe(CN)6 ACTIVITY OF THE FIRST ENZYME (H EQUALs 1.3). pH STUDIES INDICATED T... |
1252 Arginine decarboxylase which makes its appearance in Lathyrus sativus seedlings after 24 h of seed germination reaches its highest level around 5-7 days, the cotyledons containing about 60% of the total activity in the seedlings at day 5. The cytosol enzyme was purified 977-fold from whole seedlings by steps invol... |
1253 Yeast hexokinase A (ATP:D-hexose 6-phosphotransferase, EC2.7.1.1) dissociates into its subunits upon reaction with succinic anhydride. The chemically modified subunits could be isolated in a catalytically active form. The Km values found for ATP and for glucose were of the some order as those found for the native ... |
1254 Chymotrypsinogen has been successfully renatured in solution, after reduction of its 5 disulfide bonds in 6 M guanidine-HCl. This has been made possible by the study of the renaturation of a model derivative, polyalanyl-chymotrypsinogen. The reduced derivative is shown to refold and reoxodize spontaneously, with a... |
1255 Lipid peroxide formation was initiated by the addition of either ADP-complexed Fe3+ or cumene hydroperoxide to a suspension of isolated hepatocytes. The reaction was monitored by malonaldehyde measurements. Upon the addition of iron, malonaldehyde production in the cells started immediately but ceased within 30-60... |
1256 1. Two mitochondrial forms of acetoacetyl-CoA thiolases designated as enzyme A and enzyme B were crystallized from ox liver. They could be shown to be homogenous by polyacrylamide gel electrophoresis. 2. In direction of acetoacetyl-CoA cleavage enzyme A shows a double competitive substrate inhibition when acetoace... |
1257 1. The existence of two different D-glucose-6-phosphate dehydrogenases in Pseudomonas fluorescens has been demonstrated. Based on their different specificity and their different metabolic regulation one enzyme is appointed to the Entner-Doudoroff pathway and the other to the hexose monophosphate pathway. 2. A proc... |
1258 Q-Enzyme, the enzyme that synthesizes the 1,6-alpha-glucosidic branch linkages of amylopectin, has been purified from potato to near homogeneity. The molecular weight of the enzyme is 85000. The active enzyme is a monomer, with a molar activity at pH 7.0 and 24 degrees C of 15. The energy of activation is 25 kJ/mo... |
1259 Ultracentrifugation analyses were performed on lectins under varying conditions of pH, ionic strength and temperature. It has been demonstrated that the phytohemagglutinin from Phaseolus vulgaris, the wheat germ agglutinin and the soybean agglutinin are stable when these parameters are varied, whereas the concanav... |
1261 Acinetobacter NCIB 9871 was isolated by elective culture on cyclohexanol and grows with this compound as sole source of carbon. It displays a restricted growth spectrum, being unable to grow on a wide range of alternative alicyclic alcohols and ketones. Cyclohexanol-grown cells oxidize the growth substrate at a ra... |
1262 The initial enzymic step in mercapturic acid formation is catalyzed by glutathione S-transferase. Several species of this enzyme, designated as transferases alpha, beta, gamma, delta and epsilon on the basis of increasing isoelectric points, were isolated from human liver. Evidence is presented that each of the pu... |
1263 In this report we describe a new method which is useful for measuring hydrophobic interactions between aliphatic hydrocarbon chains and proteins in aqueous environment. The method is based on partition of proteins in an aqueous two-phase system containing dextran and poly(ethylene glycol) and different fatty acid ... |
1264 Rabbit muscle phosphofructokinase, spin-labelled at its most reactive thiol group, has an electron spin resonance spectrum which is very sensitive to the binding of substrates and allosteric effectors. The spectral changes have been interpreted in terms of a concerted allosteric transition between two conformation... |
1265 A cytochrome c derivative from which iron is removed has been prepared and characterized. Several lines of evidence indicate that native and porphyrin cytochrome c have similar conformations: they have similar elution characteristics on Sephadex gel chromatography; in both proteins the tryptophan fluorescence is q... |
1267 It was shown by gel electrophoresis in sodium dodecylsulphate solution that 3-methylcrotonyl-CoA carboxylase from Achromobacter IVS is composed of two different subunits with molecular weights of about 78000 and 96000, respectively. The biotin is bound to the heavier subunit. It was previously found that 3-methylc... |
1270 Acetylated derivatives of glucagon have been prepared by reacting this hormone under various conditions with acetic anhydride. They have been chemically characterized by the use of a 14C-labeled reagent, by peptide mapping techniques following hydrolysis by pronase and chymotrypsin, and by spectroscopy. Acetylatio... |
1271 A periplasmic aminoendopeptidase from Escherichia coli has been purified to hemogeneity. It is a monomer of molecular weight 45000 and containing one -- SH group that is necessary for catalytic activity. The study of its substrate specificity indicated that the enzyme has both aminopeptidase and endopeptidase acti... |
1272 In this study of the binding properties of inositol hexaphosphate and 2,3-bisphosphoglycerate to chicken and human deoxyhemoglobin and carboxyhemoglobin were compared. It appeared that in all cases the binding to chicken hemoglobin is much stronger than to human hemoglobin. This is very probably due to the fact th... |
1273 In the large granule fraction of rat liver, the density distribution of inhibitor-sensitive neutral ribonuclease is similar to that for acid hydrolases and its density distribution is similarly modified by Triton WR-1339 accumulation in lysosomes. Particulate neutral ribonuclease is latent; the enzyme is unmasked ... |
1275 Gamma-Glutamyl transpeptidase was isolated from sheep kidney cortex as an apparently homogeneous, highly active protein. At optimal pH and in the absence of acceptors, the enzyme catalyzes the release of about 510 mumol of p-nitroaniline per mg protein per min from the model substrate L-gamma-glutamyl-p-nitroanili... |
1276 1. A radiochemical method for the studies on the microsomal UDPglucuronic acid metabolism has been developed. 2. The rat liver microsomes caused a rapid hydrolysis of UDPglucuronic acid to D-glucuronic acid 1-phosphate and further although much slower to free D-glucuronic acid. In Tris-HCl buffer (pH 7.4) they wer... |
1277 |
1278 1. On incubation with the isolated rat submaxillary gland plasma membranes, [1-14C]palmitoyl-CoA was incorporated mainly into phosphatidylcholine and hydrolysed to [1-14C]palmitic acid and CoASH. 2. The addition of lysophosphatidylcholine enhanced the incorporation into phosphatidylcholine and lowered the hydrolys... |
1279 Hydrogen-deuterium exchange in 2H20 solutions of the two redox states of horse heart cytochrome c was investigated at 20 degrees C, pH 7, by mass spectrometry and infrared spectroscopy. Mass spectrometry indicates that ferricytochrome has 20 hydrogens unexchanged after 24 h, 28 hydrogens exchanging between 10 min ... |
1280 The hydroxylase activities observed in extracts of Pseudomonas putida ORC after growth on orcinol and resorcinol as sole source of carbon have been purified to homogeneity. Both enzymes were shown to be flavoproteins and to contain approximately 1 mol of FAD for each polypeptide chain, S20,W values for each enzyme... |
1289 |
1290 |
1324 The DNA of a sulfonamide-resistant Pneumococcal strain (heterozygous for sulr-c) and that of three highly resistant and persistently heterozygous cd transformants, derived by introducing sulr-c marker into a stable sulfonamide resistant strain (sulr-d), were studied to analyze the genetic basis of their merodiploi... |
1325 The sanguis and pneumoniae species of Streptococcus were used as recipients in transformations from str+ to str-r and from thy- to thy+. The str-r mutations in the two species had been previously shown to be allelic. Homology of the thy- mutations in the two species was demonstrated in the similar phenotypic prope... |
1364 |
1368 Transport of 3-O-methyl-D-glucose (3-O-MG) by Acholeplasma laidlawii cells was studied. The 3-O-MG transport system appeared to be constitutive in cells grown on 3-O-MG and glucose; the transport process depended on the concentration of substrate used and exhibited typical saturation kinetics, with an apparent Km ... |
1369 Washed cells of Salmonella enteritidis harvested from a defined medium during logarithmic growth were subjected to starvation in pH 7 phosphate buffer at 37 C. Viability was measured by slide cultures and plate counts. The survival of cell suspensions equivalent to 1 to 10 mg (dry wt)/ml was influenced by cryptic ... |
1370 A hypothesis that preferential rejection of donor markers by the hex system of pneumococcus is due to lethal double-strand breaks has been examined in terms of its implications for the extent of the excision required. Experiments reported here were directed at asking whether hex-dependent marker efficiency depends... |
1371 A microcalorimetric technique was used for studying the growth of Escherichia coli during anaerobiosis. The growth thermograms obtained are complex and the shape of curves is dependent on the hydrogen lyase activity of the cells. Fermentation balances are given for different culture conditions, and simple growth t... |
1372 The enhancement of ergot alkaloid production by tryptophan and its analogues in both normal and high-phosphate cultures is more directly related to increased dimethylallyltryptophan (DMAT) synthetase activity rather than to a lack of regulation of the tryptophan biosynthetic enzymes. Thiotryptophan [beta-(1-benzo-... |
1373 Microcalorimetry has been used to determine the affinity of whole cells of Escherichia coli for glucose, galactose, fructose, and lactose. Anaerobic growth thermograms were analyzed, and the Km and Vmax values for these energy substrates were measured at pH 7.8. Results obtained with this technique using various o... |
1374 A polyol dehydrogenase of broad specificity was purified 178-fold from extracts of the filamentous fungus Cephalosporium chrysogenum. The enzyme was found to act as an oxido-reductase in two substrate-coenzyme systems: D-sorbitol (or xylitol)-nicotinamide-adenine dinucleotide (NAD) and D-mannitol-nicotinamide aden... |
1377 beta-N-acetylglucosaminidase (EC 3.2.1.30) has been purified from Escherichia coli K-12 to near homogeneity based on polyacrylamide gel electrophoresis in both 0.5% sodium dodecyl sulfate and in 6 M urea at pH 8.5. The purified enzyme shows a pH optimum of 7.7 and the Km for p-nitrophenyl-beta-D-2-acetamido-2-deox... |
1378 Extracts of dormant microcysts of Polysphondylium pallidum demonstrate pH optima for the hydrolysis of casein at 3.5 and 6.0. During germination the intracellular pH 6.0 caseinolytic specific activity does not change significantly. The pH 6.0 protease is also active on azo-albumin, revealing the same developmental... |
1379 Rifampin-resistant mutants were isolated from Lactobacillus casei S1 and examined for possible simultaneous alteration in nutritional properties. Among the 36 mutants obtained either spontaneously or after mutagenesis with 2-aminopurine, 22 were found to be altered with respect to the specific growth requirements.... |
1380 Deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase (EC 2.7.7.6) from Acinetobacter calcoaceticus was purified to apparent homogeneity and its properties were compared with those of the Escherichia coli B enzyme. The molecular weights of the two native active enzymes as well as their alpha and ... |
1381 The urea-hydrolyzing activity of a T-strain mycoplasma was studied in experiments using whole cells and cell-free enzyme preparations by measuring the release of 14CO2 from [14C]urea. Under the conditions used, the urea concentration optimum is approximately 5.6 X 10(-3) M urea. The activity is soluble and not mem... |
1382 An arginine decarboxylase has been isolated from a Pseudomonas species. The enzyme is constitutive and did not appear to be repressed by a variety of carbon sources. After an approximately 40-fold purification, the enzyme appeared more similar in its properties to the Escherichia coli biosynthetic arginine decarbo... |
1383 3-Deoxy-arabino-heptulosonic acid 7-phosphate synthase, prephenate dehydratase, tryptophan synthase, and 2,3-dihydroxybenzoylserine synthase enzyme activities are derepressed in wild-type Escherichia coli K-12 cells grown on Fe3+-deficient medium. This derepression is reversed when FeSO4 is added to the growth med... |
1384 When Streptomyces alboniger spores were grown in Hickey-Tresner broth containing 5 muM ethidium bromide, a high frequency of permanently cured aerial mycelia-negative (am-) colonies was recovered. The appearance an am- colonies was time dependent: a very low frequency (0.3%) at zero time, a maximum (9 to 21%) afte... |
1385 Highly active, essentially homogeneous, preparations of ferrocytochrome c oxidase (EC 1.9.3.1) have been obtained from both yeast and beef heart by extraction with cholate, fractionation with ammonium sulfate, and replacement of cholate by Tween 20. The molecular weights of the resultant proteins equal 260 +/- 23 ... |
1386 Methylglyoxal synthetase, which catalyzes the conversion of dihydroxyacetone phosphate to methylglyoxal and inorganic phosphate, has been isolated and crystalized in good yields from Proteus vulgaris. The enzyme was shown to be homogeneous by a variety of criteria and was found to be a dimer (Mr = 135,000; s20,w =... |
1387 Beef kidney 3-hydroxyanthranilic acid oxygenase has been purified to homogeneity. It is a single subunit protein of Mr = 34,000 +/- 2,000 with a frictional coefficient (f/f0) of about 1.1. The enzyme readily aggregates to form, apparently inactive, higher molecular weight oligomers. The very rapid loss of enzyme a... |
1388 A monolayer reaction system employing tripropionin and siliconized glass beads was used to study the effects of taurodeoxycholate and colipase on the catalytic activity, interfacial stability, and interfacial affinity of porcine pancreatic lipase B (EC 3.1.1.3) The stability and catalytic activity of lipase at the... |
1389 The obligate intracellular parasitic bacterium, Rickettsia prowazeki, has a carrier-mediated transport system for ADP and ATP. The transport of nucleotides was measured by membrane filtration assays; the assay was shown not to harm the relatively labile rickettsiae. The nucleotide transport system was shown to res... |
1390 Rabbit liver purine nucleoside phosphorylase (purine nucleoside: orthophosphate ribosyltransferase EC 2.4.2.1.) was purified to homogeneity by column chromatography and ammonium sulfate fractionation. Homogeneity was established by disc gel electrophoresis in presence and absence of sodium dodecyl sulfate, and iso... |
1391 Three homogeneous preparations of D-alanine carboxypeptidases I have been obtained from Escherichia coli strain H2143, termed enzymes IA, IB, and IC. Enzyme IA purified from the membrane after extraction with Triton X-100 appeared on sodium dodecyl sulfate gel electrophoresis to be a polypeptide doublet whose mono... |
1392 The binding of p-hydroxymercuribenzoate to human methemoglobin causes a perturbation of the visible heme abosrption spectrum which is expressed by an increase in absorbance in the high spin band regions, 480 to 510 nm and 590 to 640 nm, concomitant with a decrease in absorbance in the alpha- and beta-band absorpti... |
1393 The observed static difference spectrum produced by inositol hexaphosphate binding to methemoglobin is the sum of a very fast and a slow spectral transition. The more rapid absorbance change is too fast to be measured by stopped flow techniques, whereas the slow change exhibits a half-time in the range 1 to 6 s. F... |
1395 The principal component of normal adult human hemoglobin Ao, was equilibrated under various conditions with 13CO2. In addition, derivatives containing specifically carbamylated NH2-terinal groups in alpha or beta chains, or both, were prepared by treatment with cyanate, and equilibrated likewise to allow the ident... |
1396 Cell-free extracts of rat brain catalyze the reactions of the purine nucleotide cycle. Ammonia is formed during the deamination but not the amination phase of the cycle. The activity of adenylate deaminase in brain is sufficient to account for the maximum rates of ammonia production that have been reported. The ac... |
1397 A method has been devised which permits the observation of the loss of active sites promoted by aggregation of alpha-chymotrypsin. When alpha-chymotrypsin in unbuffered solution at pH 7 is mixed with buffered proflavin by stopped flow instrumentation to give a final pH of 3.89, a decrease in active sites occurs, a... |
1418 A method has been developed for the preparation of streptococcal nuclease B by batch adsorpton to diethylaminoethyl-cellulose. The enzyme is homogeneous with respect to nuclease activity and is suitable for use as an antigen in measurement of anti-deoxyribonuclease B levels in sera. |
1447 Mouse skin contains a NADPH-dependent, aryl hydrocarbon hydroxylase (AHH), which is inducible by polycyclic aromatic hydrocarbons. In general, unsubstituted polycyclic hydrocarbons caused a greater induction of epidermal AHH than substituted one (1,2,3,4-dibenzanthracene greater than 1,2,5,6-dibenzanthracene great... |
1448 The collagens are the major structural glycoproteins of connective tissues. A unique primary structure and a multiplicity of post-translational modification reactions are required for normal fibrillogenesis. The post-translational modifications include hydroxylation of prolyl and lysyl residues, glycosylation, fol... |
1449 The extracts of granules of human polymorphonuclear leukocytes hydrolyzed a variety of proteins including human and bovine hemoglobin, human fibrinogen, human and bovine serum albumin, bovine elastin, and casein. The hydrolysis of all the proteins except fibrinogen and elastin was increased by addition of urea. Va... |
1459 Injection of an homogenate of identified neuron R15 into the hemocele of Aplysia produced a weight increase of 3-10% within 90 min. Control injections of several other identified neurons or of seawater, were ineffective. The weight increase occurred even when the animals were maintained in 5% hyperosmotic seawater... |
1460 The intracellular pH (pHi) of squid giant axons has been measured using glass pH microelectrodes. Resting pHi in artificial seawater (ASW) (pH 7.6-7.8) at 23 degrees C was 7.32 +/- 0.02 (7.28 if corrected for liquid junction potential). Exposure of the axon to 5% CO2 at constant external pH caused a sharp decrease... |
1521 1. Diethyl ether, which is known to be partly metabolized in vivo, has been found to show an O2 uptake with the rat liver microsomal membranes; a similar reaction is given with other short chain aliphatic ethers, isoproply and n-butyl ether. 2. The "etherase" reaction is optimal at pH 7.2-7.4 and is not accompanie... |
1522 |
1572 This study examines the renal response to moderate hyperventilation in healthy man. Eight men hyperventilated for 26 hr (PaCO2 approximately 30 to 32 mm Hg) in normoxia (barometric pressure, PB approximately 740 mm Hg) and hypobaric hypoxia (PB approximately530 mm Hg). Anaerobic samples of arterial blood and urine... |
1744 We have examined three mutants of Klebsiella aerogenes whose genetic lesions (glnB, glnD, and glnE) are in loci unlinked to the structural gene for glutamine sythetase (glnA) and in which the control of both the level and state of adenylylation of glutamine synthetase is altered. Each mutation alters a different c... |
1745 Clonal mouse neuroblastoma cells without tyrosine 3-monooxygenase [EC 1.14.16.2; tyrosine hydroxylase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating)] activity were fused with normal cells from embryonic mouse sympathetic ganglia. One of the 37 hybrid cell lines obtained possesses high tyr... |
1746 Under aerobic conditions that are likely to prevail in chloroplasts in vivo, the optimal concentration of ferredoxin for cyclic photophosphorylation was found to be equal to that required for NADP reduction and about one-tenth of that needed for cyclic photophosphorylation under anaerobic conditions. In the presen... |
1748 Stimulation with phytohemagglutinin of the leukocytes from six of the seven known individuals with UDP-galactose 4-epimerase (= UDP-glucose 4-epimerase; EC 5.1.3.2) deficiency consistently resulted in the appearance of epimerase activity in the cultured cells. A long-term lymphoblast culture derived from one proba... |
1749 beta-Bungarotoxin, a pre-synaptic neurotoxin isolated from the venom of the snake Bungarus multicinctus, has been shown to modify release of neurotransmitter at the neuromuscular junction. In this communication, we demonstrate that beta-bungarotoxin is a potent phospholipase A2 (phosphatide 2-acyl hydrolase, EC 3.... |
1750 An unsaturated fatty acid-requiring mutant derived from Chinese hamster ovary (CHO) cells has been isolated and characterized. This mutant grows normally when oleate or other unsaturated fatty acids are supplemented in the growth medium. Unlike the wild-type CHO cells, growth stops when medium is deprived of unsat... |
1751 The method of DNA alkaline elution was applied to a study of the formation and resealing of DNA single-strand breaks after irradiation of human fibroblasts with ultraviolet light (UV). The general features of the results were consistent with current concepts of DNA excision repair, in that breaks appeared rapidly ... |
1752 Highly purified platelet glucose-6-phosphate dehydrogenase (G6PD; D-glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49) can be modified in its isoelectric point and its molecular specific activity by extracts of some leukemic granulocytes. The "G6PD modifying factors" are relatively small molecules (molecular... |
1753 Raising day-old chicks on diets lacking copper severely depressed the activity of lysyl oxidase, a copper metalloenzyme in connective tissue. Administration of CuSO4 either through the diet or through intraperitoneal injections restored the lysyl oxidase activity in aortic tissue. Two hours after the chicks receiv... |
1754 The cellular content of acetyl-CoA carboxylase [acetyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] in Saccharomyces cerevisiae is reduced by the addition of long-chain fatty acids to the culture medium. Mutant strains of S. cerevisiae defective in acyl-CoA synthetase [acid:CoA ligase (AMP-forming), EC 6.2... |
1755 Villus tip cells and crypt cells of rat jejunal mucosa were separated by the planning procedure of Imondi et al. and were studied with respect to their activities of the enzymes of the gamma-glutamyl cycle and glutathione content. The villus tip cells exhibit much higher gamma-glutamyl transpeptidase activities th... |
1756 Addition of dimethylsulfoxide at concentrations of 1% and 2% (vol/vol) to cells of mouse neuroblastoma clone NIE-115 in the confluent phase of growth resulted in the production of morphologically differentiated cultures with extensive process formation. Cell maintained in 2% dimethylsulfoxide remained in a stable ... |
1757 Stoichactis helianthus toxin, a protein derived presumably from the nematocysts, was purified to homogeneity. It has a molecular weight of about 16,000, an isoelectric pH of 9.8, and it contains approximately 3.7% carbohydrate. It is powerfully hemolytic for erythrocytes derived from a variety of animal species, t... |
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