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At least 19 recordsLinked to original sources
PubMed1975

Mechanistic studies on the rat kidney flavoenzyme L-alpha-hydroxy acid oxidase.

The falvoenzyme L-alpha-hydroxy acid oxidase from rat kidney [T.H Cromartie and C.T. Walsh (1975), Biochemistry 14, 2588] fails to catalyze the elimination of HCl form D,L-beta-chlorolactate, although this compound is a substrate for oxidation by the enzyme. Deuterium isotope effects demonstrate that proton removal from the alpha carbon of alpha-hydroxy acids is fully rate limiting, a finding in agreement with observations on L-lactate dehydrogenase from yeast [F. Lederer (1974), Eur. J. Biochem. 46, 393] which also does not promote elimination from D,L-beta-chlorolactate. Both D-alpha-hydroxy acid oxidase were found to be rapidly and irreversibly inactivated by the acetylenic substrate 1-hydroxy-3-butynoate. The partially purified dehydrogenase was observed to be inactivated within 10 min by 6.8 times 10(-8) M hydroxybutynoate. For the more extensively studied oxidase, inactivation was found to occur after 25 catalytic events, inactivation occurring by covalent addition of the inactivator to the coenzyme. A stoichimometry of one molecule of hydroxybutynoate per flavine was found, and the time course of inactivation was unaffected by the presence of thiols. The oxidase could also be inactivated by prolonged incubation of the enzyme with 2-hydroxy-3-butenoate, and inactivation which could be completely prevented by the presence of thiolds. Since the inactivation with hydroxybutenoate also left the flavine coenzyme unaltered, the inactivation was attributed to Michael addition of nucleophiles on the enzyme of the ketobutenoate product. Several 4-alkyl-substitued 2-hydroxy-3-butynoates were also observed to inactivate the oxidase by both coenzyme modification and random addition to the apoenzyme. It is proposed that the inactivation may occur by nucleophilic addition of a C4 allenic carbanion to the oxidized flavine coenzyme.

Alcohol Oxidoreductases↗
PubMed1977

Significance and taxonomic value of iso and anteiso monoenoic fatty acids and branded beta-hydroxy acids in Desulfovibrio desulfuricans.

The fatty acids obtained from extractable lipids of the anaerobic sulfate bacterium Desulfovibrio desulfuricans were identified. Saturated and monoenoic iso (C15-C19) and anteiso (C15, C17) fatty acids and saturated normal (C14-C18) and monoenoic normal (C16, C18) fatty acids were shown to be shown to be present by capillary gas chromatography-mass spectrometry. Iso and anteiso beta-hydroxy fatty acids were analyzed as trimethylsilyl ethers in the same way. The position of methyl branches in the monoenoic fatty acids was determined from characteristic fragment ions in the mass spectra of their methyl esters. Disilyloxy methyl esters, prepared by derivatization of the mono unsaturated methyl esters and analyzed by capillary gas chromatography-mass spectrometry, provided the position of double bonds. The monoenoic fatty acids identified in this way were normal (delta7-C16:1, delta9-C16:1, delta9-C18:1, delta11-C18:1), iso (delta7-C15:1, delta9-C16:1, delta9-C17:1, delta11-C18:1, delta11-C19:1), and anteiso (delta7-C15:1, delta9-C17:1). Iso delta9-C17:1 fatty acid is present as the major component. The occurrence of these monoenoic fatty acids in this bacterium is of taxonomical importance.

Chromatography, Gas↗
PubMed1975

Rat kidney L-alpha-hydroxy acid oxidase: isolation of enzyme with one flavine coenzyme per two subunits.

L-alpha-Hydroxy acid oxidase (listed as EC 1.4.3.2, L-amino acid: O2 oxidoreductase) has been purified 100-fold from rat kidney to apparent homogeneity by gel electrophoresis. A subunit molecular weight of 47,500 was found by sodium dodecyl sulfate gel electrophoresis, but in contrast to previous reports, the enzyme has been found to have a molecular weight of ca. 200,000 by Sephadex gel filtration and by dodecyl sulfate gel electrophoresis of the enzyme cross-linked with dimethyl suberimidate. A somewhat higher value was found by sedimentation equilibrium, but a tetrameric structure for the active enzyme is definitely established. The enzyme was found to contain the FMN coenzyme at a concentration of one FMN/102,000 daltons or one flavine/two subunits, a highly unusual finding. This ratio was determined from spectroscopic analysis of the FMN in lyophilized samples of the enzyme and by titration of the coenzyme with the flavine specific enzyme inactivator 2-hydroxy-3-butynoate. The enzyme has the same specific activity as a crystalline sample of the enzyme reported to have twice as much flavine/milligram.

Amino Acid Oxidoreductases↗
PubMed1975

Ultrastructural localization of L-alpha-hydroxy acid oxidase in rat liver perioxisomes.

The localization of L-alpha-hydroxy acid oxidase in rat liver peroxisomes was studied using slight modifications of the Shnitka and Talibi (1971) method. Best results were obtained with formaldehyde fixation and incubation with glycolate as substrate. Following incubation the copper ferrocyanide reaction product was amplified with 3,3'-diamino-benzidine according to Hanker et al. (1972a,b). Dense reaction product was visible in hepatocyte peroxisomes by light and electron microscopy. Some diffusion of enzyme and/or reaction product into the adjacent cytoplasm occurred around the peroxisomes. Apparent non-specific deposits occurred on the plasmalemma, in the nucleus, and occasionally over mitochondria. Glutaraldehyde fixation severely inhibited enzymatic activity, and the enzyme showed less activity toward L-lactate and DL-alpha-hydroxybutyrate.

Alcohol Oxidoreductases↗
PubMed1976

Ultrastructural localization of catalase and L-alpha-hydroxy acid oxidase in microperoxisomes of Hydra.

The ultrastructural localization of catalase and L-alpha-hydroxy acid oxidase (LalphaHAO) was studied in two species of Hydra. Diaminobenzidine reaction product of catalase activity was present in small round or elongated bodies resembling microperoxisomes in the epitheliomuscular, digestive and gland cells. They were closely related to the endoplasmic reticulum, and were often found in proximity to deposits of lipid and glycogen. Reaction product of LalphaHAO activity was also associated with the microperoxisomes. With rapidly oxidized substrates, such as L-lactic acid, reaction product diffused into the cytoplasm around the microperoxisomes. With slowly oxidized substrates, such as DL-alpha-hydroxyisovaleric acid, reaction product was restricted to the matrix of the microperoxisomes. No reaction product was present in the microperoxisomes in the absence of substrate or with D-lactic acid. The rate of substrate oxidation measured biochemically roughly paralleled the amount of cytochemical reaction product deposited with different substrates. Microperoxisome-like bodies reactive for LalphaHAO were also found in the epidermal cnidoblasts; however, catalase could not be demonstrated in them. This study provides the first cytochemical evidence for the presence of an H2O2-producing oxidase in microperoxisomes.

Alcohol Oxidoreductases↗
PubMed1978

Effects of dihydroxy bile acids and hydroxy fatty acids on the absorption of oleic acid in the human jejunum.

Perfusion studies of the normal human jejunum were performed to test whether dihydroxy bile acids and hydroxy fatty acids inhibit the absorption of oleic acid, since previous reports documented their inhibitory effects on the absorption of several other organic solutes. 3 mM deoxycholate and 7 mM glycodeoxycholate inhibited the absorption of 3 mM oleic acid in isotonic micellar solutions while inducing net fluid secretion. Similarly, fractional absorption of oleic acid decreased in the presence of hydroxy fatty acids. However, only the changes induced by 2 mM ricinoleic acid could be distinguished from changes induced by an increase in total fatty acid concentration. Under all experimental conditions, close linear relationships existed between net water movement and fractional absorption of glucose, xylose, and fatty acids, as well as between the absorption rates of these solutes. In contrast, net fluid secretion induced by hypertonic D-mannitol (450 mosmol/liter) had no effect on solute absorption. Our data and observations in the literature do not allow formulation of a hypothesis which would adequately define all effects of dihydroxy bile acids and fatty acids on intestinal transport processes. The observations help explain the malabsorption of fat and other nutrients in patients with the blind loop syndrome.

Adult↗
PubMed1978

Genetics and physiological expression of beta-hydroxy acid dehydrogenase in Drosophila.

A mutant Hadnl was induced in Drosophila melanogaster and found to be deficient in beta-hydroxy acid dehydrogenase. This mutation was utilized to study the genetics and physiological expression of Had+ . Had+ was mapped to the X chromosome at 54.4 and seems to be the structural gene for the enzyme. Enzyme activity in male and female flies indicates that the gene shows both dosage compensation independent from dose effect and differential activity during ontogeny. Electrophoretic mobility data indicate that the enzyme is a dimer which forms by random association of subunits. The fact that the mutant shows no detrimental effect implies that the enzyme is dispensable, at least under laboratory conditions. The biological and technical implications of this gene--enzyme system are discussed.

Animals↗
PubMed1975

[Ascorbic, keto and hydroxy acid metabolism in the cell nuclei of certain tumors].

The authors report the results of studies on the content of ascorbic acid, pyruvic acid and the activity of malate dehydrogenase decarboxylizing (MDHD) in cell nuclei of uterine fibromyoma, glandular hyperplasia of the endometrium with epithelial proliferation, common ovarian cyst and solid cancer. It was shown that due to the glycolysis inhibited respiration an oxidated form of ascorbic acid is absent in every case, whereas the MDHD activity is not manifested. The amount of a reduced form of ascorbic and pyruvic acid in benign tumors is at the control level, but in malignant growth these indices are markedly increased.

Ascorbic Acid↗
PubMed1976

[Alpha-hydroxy-acid dehydrogenase activity in Trypanosoma cruzi].

Crude extracts of culture forms of epimastigotes, Tulahuén strain, showed activity to catalyze the reaction alpha-ketocid in equilibrium alpha-hydroxyacid linked to nicotinamide adenine dinucleotide (NAD). The enzyme utilizes the following substrates: alpha-ketobutyrate, alpha-ketoisovalerate, alpha-keto-beta-methylvalerate, alpha-ketocaproate, alpha-ketoisocaproate, alpha-ketoglutarate and pyruvate. Kinetics for the three last substrates were of the Michaelian type. For the other ketocids, curves of activity against substrate concentration exhibited a bimodal character. Km and V values for alpha-ketoisocaproate were strikingly higher than those for the other substrates. Electrophoretic separation of extracts on polyacrylamide gel and specific staining showed a single zone of enzymatic activity with similar mobility for all the alpha-OH-acids tested. This finding would indicate that the same protein is responsible for the reaction. The observations presented demonstrate that culture forms of Trypanosoma cruzi possess the ability to interconvert pyruvate in equilibrium lactate and to regenerate NAD in anaerobiosis. Although the physiological significance of the reaction with alpha-ketoacids other than pyruvate is not known, similarity of substrate of substrate spectrum between alpha-OH-acid dehydrogenase from Trypanosoma cruzi and lactate dehydrogenase ioenzyme X from mammalian and avian spermatozoa is interesting. Perhaps activity of flagella requires analogous metabolic pathways.

Alcohol Oxidoreductases↗
PubMed1992

Simultaneous determination of simvastatin and its hydroxy acid form in human plasma by high-performance liquid chromatography with UV detection.

Simvastatin (SV), an analogue of lovastatin, is the lactone form of 1',2',6',7',8',8a'-hexahydro-3,5-dihydroxy-2',6'-dimethyl-8'(2'',2''-di met hyl-1''-oxobutoxy)-1'-naphthalene-heptanoic acid (SVA) which lowers plasma cholesterol by inhibiting 3-hydroxy-3-methylglutaryl-CoA reductase. A fast, simple and accurate method for determining SV and SVA concentrations in human plasma has been developed and validated for use in the analysis of plasma samples from patients and healthy volunteers. This method involves an extraction procedure using a mixture of acetonitrile-water and reversed-phase high-performance liquid chromatography with UV detection. The procedure was linear from 20 to 1000 ng ml-1 for SV and from 25 to 1000 ng ml-1 for SVA, respectively. The method was accurate with relative errors of 5.0, 2.1 and 3.2% for human plasma controls containing 50, 250 and 500 ng ml-1 of SV, respectively. The corresponding precision was 2.3, 1.8 and 1.0% (RSD%). Similarly, relative standard deviations less than 2.3% and relative errors of less than 5.2% were obtained from human plasma controls containing SVA at identical concentrations. The method is suitable for pharmacology and pharmacokinetic studies of simvastatin.

Blood Proteins↗
PubMed1979

Subunit structure and kinetic properties of L-beta-hydroxy acid dehydrogenase of Drosophila.

L-beta-hydroxyacid dehydrogeanse (L-gulonate:NAD+ 3-oxidoreductase, EC 1.1.1.45) of Drosophila is made up of two non-identical subunits with molecular weights of 40 000 and 23 500. Michaelis constants calculated at saturating concentrations of the other substrate were 0.13 mM for NAD+, 0.85 mM for L-gulonate, 14.8 mM for L-beta-hydroxybutyrate; dissociation constants (Kia) were 2.8 mM for L-gulonate, 22 mM for L-beta-hydroxybutyrate. The maximum velocity with L-gulonate as substrate was ten-fold greater than with beta-hydroxybutyrate. As product inhibitors, both NADH and acetoacetate are competitive vs. both substrates, suggesting a rapid equilibrium random mechanism.

Animals↗
PubMed1978

Isolation of a novel sphingoglycolipid containing glucuronic acid and 2-hydroxy fatty acid from Flavobacterium devorans ATCC 10829.

A new acidic sphingoglycolipid has been isolated from a Gram-negative, glucose-non-fermentative (obligatory aerobic) bacterium, Flavobacterium devorans ATCC 10829, by thin-layer chromatography on silica gel after mild alkaline hydrolysis of the cellular lipids. Chemical degradation studies, thin-layer chromatographic behavior, IR and mass-spectrometric analysis of the original and reduced glycolipid with LiA1H4 revealed that the lipid contained glucuronic acid, long-chain bases, and fatty acids in a molar ratio of approximately 1:1:1. The major long-chain bases were identified by gas chromatography-mass spectrometry as dihydrosphingosine (d-18 :0) and longer homologues, while the N-acyl group was exclusively 2-hydroxy myristic acid. The most probable structure of this glycolipid appeared to be a ceramide glucuronic acid (N-acyl dihydrosphingosine 1-glucuronic acid).

Flavobacterium↗
PubMed1977

Detection of bacterial metabolites in spent culture media and body fluids by electron capture gas-liquid chromatography.

Electron capture gas-liquid chromatography, when used to analyze derivatized extracts of spent culture media and body fluids under specified conditions, holds promise as a tool for use by physicians, hospitals, and clinical laboratories in identifying certain diseases and disease-producing organisms. The detection of certain disease processes and the identification of disease-producing organisms are based on qualitative or large quantitative differences in EC-GLC profiles or a combination of both. Various practical procedures are given for extracting and derivatizing compounds, such as carboxylic acids, hydroxy acids, alcohols, amines, and nitrosamines. The characteristics of the parameters essential for successful analysis are discussed. Species and, in some cases, strains have been differentiated by comparing EC-GLC profiles. Metabolic products are affected by change in substrate. Media that can be reproduced from lot to lot are essential in some studies. The volatile components detected by EC-GLC in spent culture media consist mostly of bacterial metabolites, but the volatile compounds detected in body fluids may be bacterial metabolites, volatile components produced by the host in response to an infection, metabolites of cells associated with host defense, or a combination of two or more of these groups of compounds. The EC-GLC profiles obtained by analysis of synovial and cerebrospinal fluids appear to have good potential for use in diagnosing certain forms of arthritis and meningitis. Well-documented samples are essential to establishing EC-GLC profiles representative of a particular disease. A moderately priced computer would greatly aid in data processing and could be especially useful in compensating for minor changes in the retention times of peaks, which can occur as a result of column aging or when columns are renewed. An approach to the identification of components detected by EC-GLC, which makes use of electron capture gas chromatography-mass spectrometry, is presented.

Alcohols↗