[Effect of clozapine on the excretion of 3-methoxy-4-hydroxy-phenylglycol, homovanillic acid and 5-hydroxy-indole acetic acid in urine and cerebrospinal fluid].
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Azepines↗
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Results for “Hydroxy Acids”
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Phosphonoglycan. A major polysaccharide constituent of the amoeba plasma membrane contains 2-aminoethylphosphonic acid and 1-hydroxy-2-aminoethylphosphonic acid.
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Amino Acids↗
[Gamma- and amino-butyric acids and gamma-amino-beta-hydroxy-butyric acid as pharmacoprotective agents in experimental hyperoxic neuro-intoxication].
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Aminobutyrates↗
Human neutrophils employ the myeloperoxidase-hydrogen peroxide-chloride system to convert hydroxy-amino acids into glycolaldehyde, 2-hydroxypropanal, and acrolein. A mechanism for the generation of highly reactive alpha-hydroxy and alpha,beta-unsaturated aldehydes by phagocytes at sites of inflammation.
Reactive aldehydes derived from reducing sugars and lipid peroxidation play a critical role in the formation of advanced glycation end (AGE) products and oxidative tissue damage. We have recently proposed another mechanism for aldehyde generation at sites of inflammation that involves myeloperoxidase, a heme enzyme secreted by activated phagocytes. We now demonstrate that human neutrophils employ the myeloperoxidase-H202-chloride system to produce alpha-hydroxy and alpha,beta-unsaturated aldehydes from hydroxy-amino acids in high yield. Identities of the aldehydes were established using mass spectrometry and high performance liquid chromatography. Activated neutrophils converted L-serine to glycolaldehyde, an alpha-hydroxyaldehyde which mediates protein cross-linking and formation of Nepsilon-(carboxymethyl)lysine, an AGE product. L-Threonine was similarly oxidized to 2-hydroxypropanal and its dehydration product, acrolein, an extremely reactive alpha,beta-unsaturated aldehyde which alkylates proteins and nucleic acids. Aldehyde generation required neutrophil activation and a free hydroxy-amino acid; it was inhibited by catalase and heme poisons, implicating H202 and myeloperoxidase in the cellular reaction. Aldehyde production by purified myeloperoxidase required H202 and chloride, and was mimicked by reagent hypochlorous acid (HOCl) in the absence of enzyme, suggesting that the reaction pathway involves a chlorinated intermediate. Collectively, these results indicate that the myeloperoxidase-H202-chloride system of phagocytes converts free hydroxy-amino acids into highly reactive alpha-hydroxy and alpha,beta-unsaturated aldehydes. The generation of glycolaldehyde, 2-hydroxypropanal, and acrolein by activated phagocytes may thus play a role in AGE product formation and tissue damage at sites of inflammation.
Acetaldehyde↗
Modulation of the release of 9-hydroxy-octadecadienoic acid and other fatty acid derived mediators from guinea-pig pulmonary macrophages.
Non-stimulated guinea-pig pulmonary macrophages (PM) convert arachidonic acid to thromboxane B2 and 12-hydroxy-heptadecatrienoic acid, whereas linoleic acid is metabolized to two hydroxy compounds, i.e. 9-hydroxy- and 13-hydroxy-octadecadienoic acid. Coincubation of PM with immune serum (2% v/v) resulted in a profound reduction of the release of these products. This effect seemed to be due to an inhibitory action on cyclooxygenase activity. Control serum also possessed inhibitory properties towards the release of fatty acid metabolites, possibly due to an effect on phospholipase activity. Because of the radical scavenging properties of 9-hydroxy-octadecadienoic acid, the modulation of the release of this product may be an important determinant in macrophage function.
Animals↗
Analysis of amide bond formation with an alpha-hydroxy-beta-amino acid derivative, 3-amino-2-hydroxy-4-phenylbutanoic acid, as an acyl component: byproduction of homobislactone.
In the synthesis of peptidomimetics containing alpha-hydroxy-beta-amino acid, the coupling of this N(beta)-protected beta-amino acid with amine components was generally performed without the protection of its alpha-hydroxyl group. However, the formation of dipeptides in low yield was often observed when sterically hindered amine components were used. Boc-Apns-OH [Apns: (2S,3S)-3-amino-2-hydroxy-4-phenylbutanoic acid, allophenylnorstatine] (6), which is one of such beta-amino acid derivatives, is intensively employed as a core structure in the development of HIV-1 protease inhibitors. There have been no precise studies, to date, that have examined amide bond formation with alpha-hydroxy-beta-amino acid derivatives as an acyl component. To determine the cause of this low-yield reaction, we studied the amide bond formation focusing on the activation step of N(beta)-protected alpha-hydroxy-beta-amino acid by using a model coupling reaction between 6 and H-Dmt-OR [Dmt: (R)-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid] (7). A significant amount of homobislactone 9 was formed through the activation of the carboxyl group of 6 to the benzotriazole-type active esters such as OBt and OAt. In addition, this homobislactone formation was markedly increased in the presence of a catalytic amount of a base, which exhibited good correlation with the low yield of the amide bond formation, suggesting that homobislactone formation is one major reason for the low yield of the amide bond formation. Moreover, homobislactones were also formed in other derivatives of the N(beta)-protected alpha-hydroxy-beta-amino acid, suggesting a common feature of this type of amino acids. The use of a strong activation method like EDC--HOAt without base addition enhanced amide bond formation, although a small amount of homobislactone may be formed during the coupling reaction.
Aminocaproates↗
Influence of exogenous natural oils on the omega-1 and omega-2 hydroxy fatty acid moiety of sophorose lipid produced by Candida bombicola.
Candida bombicola can synthesize monohydroxy fatty acid as a moiety of sophorose lipids. The hydroxy fatty acids contained in a major lactone were identified by GC-MS, after culturing with natural oils such as coconut, rapeseed, olive, and soybean oils. Hydroxy fatty acids of C18 and C16 were always synthesized, but differences were observed among the oils regarding the positions of hydroxyl groups, unsaturation, and composition of the fatty acids. A new C17 hydroxy acid was found without addition of oil.
Brassica↗
[Hydroperoxide degradation by oat isomerase. Investigation of the reaction mechanism (author's transl)].
Oat isomerase is inhibited by hydroxyoctadecadienoic acids (monohydroxy acids) to a degree comparable with inhibition by linoleic acid hydroperoxides (LHPO). Hydroxy acids seem to combine with the enzyme like LHPO do. In an experiment on LHPO breakdown by isomerase 1-14C-hydroxy acids were added and it was examined whether the epoxyhydroxy acids are formed by an intermolecular or intramolecular mechanism. In this experiment 1-14C-labeled trihydroxy acids were formed; they arise from the hydrolysis of epoxyhydroxyoctadecenoic acids formed on their part by isomerase effected LHPO-breakdown. It was determined that at least 70% of LHPO are converted by intermolecular reaction.
Edible Grain↗
Oxylipin formation in fungi: biotransformation of arachidonic acid to 3-hydroxy-5,8-tetradecadienoic acid by Mucor genevensis.
The soil fungus Mucor genevensis was shown to convert exogenous arachidonic acid to the oxylipin 3-hydroxy-5Z,8Z-tetradecadienoic acid (3-HTDE) as determined by gas chromatography/mass spectrometry. This metabolite was only found in the aqueous supernatant together with free linoleic acid, but not in the final fungal biomass. In contrast, the corresponding primary arachidonic acid metabolite (3R)-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoic acid (3-HETE), which has been earlier shown to be produced by the yeast Dipodascopsis uninucleata, could not be detected. These observations may be plausibly explained by a retroconversion by M. genevensis of arachidonic acid to linoleic acid before the latter is metabolised to 3-HTDE.
Arachidonic Acid↗
Liquid chromatography-mass spectrometry of hydroxy and non-hydroxy fatty acids as amide derivatives.
A useful method for analyzing fatty acids by liquid chromatography-mass spectrometry with an atmospheric-pressure chemical-ionization interface system has been developed. The sensitivity of six kinds of palmitamide derivatives monitored by a single ion of [M+H]+ was, in decreasing order: N-n-propylamide greater than anilide greater than N,N-diethylamide, amide greater than N,N-diphenylamide greater than N-1-naphthylamide. Individual fatty acids were identified from a mixture of amide derivatives of authentic fatty acids from C16:0 to C30:0 on a mass chromatogram. This method was used to detect both hydroxy and non-hydroxy fatty acids. Many kinds of fatty acid, including hydroxy fatty acids of the rat brain, were detected in a single run.
Animals↗
Organic acids and branched-chain amino acids in body fluids before and after multiple exchange transfusions in maple syrup urine disease.
We successfully treated a critically ill infant with the classical type of maple syrup urine disease by multiple exchange transfusions via a peripheral artery and vein and with positive calorie supplementation in the early stage of therapy. Clinical improvement was definite after the plasma leucine level fell below 1 mmol/l. There was a close linear correlation between plasma concentrations of branched-chain amino acids and their corresponding branched-chain alpha-keto acids and branched-chain alpha-hydroxy acids. alpha-Hydroxy acids were more easily excreted in the urine than alpha-keto acids and amino acids. Our studies on urinary organic acids supported the existence of minor metabolic pathways of branched-chain alpha-keto acids, although they were not thought to be important in eliminating accumulated alpha-keto acids. Urinary excretion of succinic acid and alpha-ketoglutaric acid, which are components of the citric acid cycle, increased transiently during the patient's convalescence. The cerebrospinal fluid/plasma ratios for branched-chain amino acids, alpha-keto acids, and alpha-hydroxy acids were very high before the transfusions and decreased after improvement. The cerebrospinal fluid/plasma ratios for 5-carbon acids, alpha-ketoisovaleric acid and alpha-hydroxyisovaleric acid were much higher than for other branched-chain acids not only in the patient but also in normal controls. Cerebrospinal fluid levels of alpha-ketoisocaproic acid and alpha-hydroxyisovaleric acid were as high as 1 mmol/l in our patient.
Amino Acids, Branched-Chain↗
Glutaric aciduria Type II.
Two infants have been studied with glutaric aciduria Type II. The clinical presentation was of an overwhelming illness very early in life; both infants died in the neonatal period. One had dysmorphic features. An acrid odor may be a clue to the diagnosis. Neonatal acidosis, hypoglycemia, and hyperammonemia are characteristic. Organic acid analysis revealed massive lactic aciduria and glutaric aciduria. A variety of other dicarboxylic acids and hydroxy acids and amino acids were found in elevated amounts in body fluids, along with elevated concentrations of butyric, isobutyric, 2-methylbutyric, and isovaleric acids. The pattern of metabolites accumulated is consistent with deficient activity of a number of acyl-CoA dehydrogenases.
Amino Acids↗
THE REDUCTION OF 5-OXODECANOIC ACID BY NORMAL BAKER'S YEAST.
1. A description is given of the course of the reduction of 5-oxodecanoic acid to 5-hydroxydecanoic acid by intact cells of baker's yeast and of the influence of pH on this reduction. As the pH of the medium is decreased the rate of uptake of the keto acid by yeast increases. However, the more the rate of uptake increases the more rapidly the yeast is poisoned by the keto acid or hydroxy acid or both. Consequently the optimum pH is at approx. 5. 2. In baker's yeast the conversion of 5-oxodecanoic acid takes place mainly in the mitochondria. 3. The conversion is strongly influenced by ATP, NADPH and Mg(2+) or Mn(2+), and to a smaller extent by CoA.SH. The NADP can only partly be replaced by NADH. Thus the reduction seems to be NADPH-dependent. A mechanism for the conversion is proposed. 4. Like the reduction by intact cells, the reduction by an isolated mitochondrial fraction proceeds stereospecifically.
Adenosine Triphosphate↗
Quantitative determination of hydroxy fatty acids as an indicator of in vivo lipid peroxidation: oxidation products of arachidonic and docosapentaenoic acids in rat liver after exposure to carbon tetrachloride.
An improved gas chromatography-mass spectrometry method has been applied to the quantitation of both in vitro and in vivo products of lipid peroxidation in rat liver stimulated with carbon tetrachloride. The method avoids problems of autoxidation of unsaturated fatty acids during sample preparation, and the sensitivity permits assays on as little as 1 mg of tissue. This permits small samples of tissue to be obtained by biopsy from the same organ, thus making it possible to perform in vivo time studies on a single animal. Lipids from whole tissue or cell preparations are simultaneously extracted and reduced by catalytic hydrogenation and then saponified and derivatized to their pentafluorobenzyl esters and trimethylsilyl ethers. Quantitation is accomplished by negative ion chemical ionization gas chromatography-mass spectrometry, using either deuterated compounds or naturally occurring fatty acid metabolites as internal standards. Hydroxy fatty acids which result from reduction of the hydroperoxides of arachidonic and docosapentaenoic acids are found to increase within 20 min after exposure of liver or hepatocyte suspensions to carbon tetrachloride.
Animals↗
Factors affecting the formation of 10-hydroxystearic acid from oleic acid by a ruminal strain of Enterococcus faecalis.
A ruminal strain of Enterococcus faecalis was characterised with respect to its ability to hydrate oleic acid to 10-hydroxystearic acid. Hydroxy fatty acid was produced after growth had ceased and the carbon source was almost exhausted. Hydroxy fatty acid production was equally rapid whether the inoculum had been grown in the presence of oleic acid or not, and almost complete conversion was achieved when oleic acid was present at a concentration of up to 0.5% (v/v). Incubation under a hydrogen headspace did not result in biohydrogenation of oleic acid. In pH-controlled batch culture the proportion of oleic acid hydrated varied with the pH of incubation, with more hydration at lower pH. Growth was retarded in the presence of 0.1% (v/v) linoleic acid, inhibited by the same concentration of linolenic acid and did not result in the formation of hydrated products from these substrates. If this organism is able to transform oleic acid in the rumen then the only product likely to be formed is 10-hydroxystearic acid.
Animals↗
Carbanion versus hydride transfer mechanisms in flavoprotein-catalyzed dehydrogenations.
The present understanding of the mechanisms by which flavoproteins oxidize amino acid or hydroxy acids to the respective imino or keto acids is reviewed. The observation that many of these enzymes catalyze the elimination of HBr or HCl from the appropriate beta-halogenated substrate was long considered evidence for a carbanion intermediate. Recent structural and mechanistic studies are not compatible with the intermediacy of carbanions in the reactions catalyzed by d-amino acid oxidase and flavocytochrome b(2). In contrast, the data are most consistent with mechanisms involving direct hydride transfer.
Amino Acids↗
Relative effects of flurbiprofen on platelet 12-hydroxy-eicosatetraenoic acid and thromboxane A2 production: influence on collagen-induced platelet aggregation and adhesion.
Flurbiprofen has been shown to inhibit cyclo-oxygenase metabolism of arachidonic acid to thromboxane A2 (TxA2), resulting in the inhibition of platelet aggregation. Recently, our laboratory reported that the "irreversible" phase of platelet aggregation and adhesion were regulated, in part, by the lipoxygenase metabolism of arachidonic acid to 12-hydroxy-eicosatetraenoic acid (12-HETE) in platelets, and that selective inhibition of one enzyme i.e. either cyclo-oxygenase or lipoxygenase, resulted in paradoxical effects on the metabolism of arachidonic acid and platelet response related to the other pathway. Therefore, we performed experiments to assess the relative effects of flurbiprofen on TxA2 and 12-HETE synthesis, and on collagen-induced platelet aggregation and platelet adhesion to collagen-coated surfaces. "Irreversible" collagen-induced platelet aggregation was only partially inhibited by pre-incubation with 1 x 10(-6) M flurbiprofen, while TxA2 production was elevated and 12-HETE production was maximally inhibited in these platelets. At this concentration of flurbiprofen (1 x 10(-6)M), collagen-induced platelet adhesion was also reduced by 50%. At higher concentrations of flurbiprofen, both platelet aggregation and adhesion were further reduced, with a corresponding inhibition of TxA2 production. Thus it appears that the lipoxygenase pathway of arachidonic acid metabolism in platelets is not only inhibited by flurbiprofen, but is more sensitive to inhibition by flurbiprofen than the cyclo-oxygenase pathway. This differential effect of flurbiprofen on arachidonic acid metabolism in the platelet is related to differential effects on platelet function.
12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
Detection of metabolites by frequency-pulsed electron capture gas-liquid chromatography in serum and cerebrospinal fluid of a patient with Nocardia infection.
Serum (SR) and cerebrospinal fluid (CSF) from a patient suspected of having tuberculous meningitis were submitted to our laboratory for analysis by frequency-pulsed electron capture gas-liquid chromatography (FPEC GLC). The samples were tested for the presence of carboxylic acids, alcohols, hydroxy acids, and amines by methods described previously (C. C. Alley, J. B. Brooks, and D. S. Kellogg, Jr., J. Clin. Microbiol. 9:97-102, 1977; J. B. Brooks, C. C. Alley, and J. A. Liddle, Anal. Chem. 46:1930-1934, 1974; J. B. Brooks, D. S. Kellogg, Jr., M. E. Shepherd, and C. C. Alley, J. Clin. Microbiol. 11:45-51, 1980; J. B. Brooks, D. S. Kellogg, Jr., M. E. Shepherd, and C. C. Alley, J. Clin. Microbiol. 11:52-58, 1980). The results were different from previous FPEC GLC profiles of SR and CSF from patients with known tuberculous meningitis. Both the SR and CSF contained several unidentified compounds that were not previously detected in tuberculous meningitis or any of our other studies of body fluids. Nocardia brasiliensis was later isolated from the patient. Detection of these metabolites by FPEC GLC could prove to be useful for rapid diagnosis of Nocardia disease, and their identification will provide a better understanding of metabolites produced by Nocardia sp. in vivo.
Amines↗