Effect of various bivalent cations and chelating agents on oxidative decarboxylation of α-keto acids

1966 ◽  
Vol 128 (3) ◽  
pp. 574-576 ◽  
Author(s):  
Taro Hayakawa ◽  
Masahiro Hirashima ◽  
Minoru Hamada ◽  
Masahiko Koike
Keyword(s):  
Chelating Agents ◽  
Oxidative Decarboxylation ◽  
Bivalent Cations ◽  
Keto Acids

scholarly journals PSXIV-19 Effect of alpha-lipoic acid on productive parameters and ruminal VFA profile in sheep

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 437-438
Author(s):  
Carolina Robles ◽  
Laura Gonzáles Davalos ◽  
Ofelia Mora ◽  
Yesmin Hermanadez ◽  
Armando Shimada ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Lipoic Acid ◽  
Insulin Receptors ◽  
Daily Weight Gain ◽  
Oxidative Decarboxylation ◽  
Alpha Lipoic Acid ◽  
Randomized Design ◽  
Keto Acids ◽  
Mechanism Research

Abstract Alpha lipoic acid (LA) is a potent nutritional antioxidant. It is a derivate of octanoic acid containing a cyclic disulfide bond. An LA complex with lysine-lipoamide, functions as a co-factor in the mitochondrial dehydrogenase that catalyzes the oxidative decarboxylation of α-keto acids. In this reaction, LA is reduced to dihydrolipoic acid (DHLA), which interacts with reactive oxygen species, and LA can also inactivate free radicals. Another important role of DHLA is in signal transduction by activating insulin receptors, which causes glucose transporters translocation from cytoplasm to the cell surface. Due to its potential antioxidant effect at ruminal level, the aim of this study was to evaluate the effect of fed LA on productive parameters, ruminal fatty volatile fatty acid (VFA) concentration and blood glucose of sheep. Sixty-four, two-months-old, crossbred lambs were penned in groups of four, divided into four treatments: 0, 40, 80, and 120 ppm LA in diet. During 84 days, every 28 days on two consecutive days, animals were weighed (to determine average daily weight gain, DWG), blood and ruminal fluid were taken for glucose and VFA quantification, respectively. All variables were analyzed in a completely randomized design. DWG was statistically higher in those animals receiving 80 ppm (250 g) as compared to the rest (200, 188, 180 g for 120, 40, 0 ppm, respectively) (P < 0.0001). No differences in blood glucose or ruminal VFA were found (P > 0.1). LA could improve the productive performance of sheep; however, it would be necessary to study the role of LA and its effects on the ruminal microbiome and its action mechanism. Research support by Project PAPIIT-UNAM IN211518

On the mechanism of oxidative decarboxylation of α-keto acids

1958 ◽  
Vol 29 (1) ◽  
pp. 218-219 ◽  
Author(s):  
D.R. Sanadi ◽  
Martha Langley ◽  
Fred White
Keyword(s):  
Oxidative Decarboxylation ◽  
Keto Acids

Hypervalent Iodine(III)-Mediated Oxidative Decarboxylation of β-Keto Acids

2017 ◽  
Vol 6 (3) ◽  
pp. 262-264 ◽  
Author(s):  
Zhipeng Yuan ◽  
Tiantian Zhao ◽  
Tianyang Yu ◽  
Junru Wang ◽  
Hao Wei
Keyword(s):  
Hypervalent Iodine ◽  
Oxidative Decarboxylation ◽  
Keto Acids

scholarly journals Mechanistic insights into the dual activities of the single active site of l-lysine oxidase/monooxygenase from Pseudomonas sp. AIU 813

2020 ◽  
Vol 295 (32) ◽  
pp. 11246-11261 ◽  
Author(s):  
Duangthip Trisrivirat ◽  
Narin Lawan ◽  
Pirom Chenprakhon ◽  
Daisuke Matsui ◽  
Yasuhisa Asano ◽  
...  
Keyword(s):  
Oxidative Decarboxylation ◽  
Single Turnover ◽  
Imino Acid ◽  
Keto Acids ◽  
Imino Acids ◽  
Dynamics Simulations ◽  
Enzyme Denaturation ◽  
Hydrolysis Of ◽  
Lysine Oxidase

l-Lysine oxidase/monooxygenase (l-LOX/MOG) from Pseudomonas sp. AIU 813 catalyzes the mixed bioconversion of l-amino acids, particularly l-lysine, yielding an amide and carbon dioxide by an oxidative decarboxylation (i.e. apparent monooxygenation), as well as oxidative deamination (hydrolysis of oxidized product), resulting in α-keto acid, hydrogen peroxide (H2O2), and ammonia. Here, using high-resolution MS and monitoring transient reaction kinetics with stopped-flow spectrophotometry, we identified the products from the reactions of l-lysine and l-ornithine, indicating that besides decarboxylating imino acids (i.e. 5-aminopentanamide from l-lysine), l-LOX/MOG also decarboxylates keto acids (5-aminopentanoic acid from l-lysine and 4-aminobutanoic acid from l-ornithine). The reaction of reduced enzyme and oxygen generated an imino acid and H2O2, with no detectable C4a-hydroperoxyflavin. Single-turnover reactions in which l-LOX/MOG was first reduced by l-lysine to form imino acid before mixing with various compounds revealed that under anaerobic conditions, only hydrolysis products are present. Similar results were obtained upon H2O2 addition after enzyme denaturation. H2O2 addition to active l-LOX/MOG resulted in formation of more 5-aminopentanoic acid, but not 5-aminopentamide, suggesting that H2O2 generated from l-LOX/MOG in situ can result in decarboxylation of the imino acid, yielding an amide product, and extra H2O2 resulted in decarboxylation only of keto acids. Molecular dynamics simulations and detection of charge transfer species suggested that interactions between the substrate and its binding site on l-LOX/MOG are important for imino acid decarboxylation. Structural analysis indicated that the flavoenzyme oxidases catalyzing decarboxylation of an imino acid all share a common plug loop configuration that may facilitate this decarboxylation.

Effects of diabetes on oxidative decarboxylation of branched-chain keto acids

1980 ◽  
Vol 239 (3) ◽  
pp. E215-E222 ◽  
Author(s):  
M. E. May ◽  
V. J. Mancusi ◽  
R. P. Aftring ◽  
M. G. Buse
Keyword(s):  
Insulin Treatment ◽  
Streptozotocin Diabetes ◽  
Diabetic Rats ◽  
Relative Increase ◽  
Oxidative Decarboxylation ◽  
Decarboxylase Activity ◽  
Mitochondrial Mass ◽  
Keto Acids ◽  
Branched Chain ◽  
Ketoacid Dehydrogenase

Oxidative decarboxylation is the first irreversible step in the degradation of leucine. The effect of streptozotocin diabetes on this reaction was studied in cell-free rat liver preparations, using [1-14C]alpha-ketoisocaproate as substrate. Diabetes increased the branched-chain ketoacid dehydrogenase (BCKD) activity (per g liver or per mg protein) of homogenates, but the ratios of homogenate BCKD activity to other mitochondrial markers remained unchanged. A cytosolic branched-chain ketoacid decarboxylase activity (15-22% of homogenate activity), which did not require NAD, CoA, or NADP, was also increased in diabetics. Insulin treatment of diabetics normalized enzyme activity in all fractions. The apparent Km of BCKD in homogenates was 43-45 microM; diabetes increased the apparent Vmax from 165 nmol x min-1 x g tissue-1 to 260 nmol x min-1 x g-1. In contrast, the Km for cytosolic alpha-ketoisocaproate decarboxylation was 270 microM in controls, and diabetes resulted in both a lower Km (210 microM) and a higher Vmax. Adrenalectomy did not affect activity in homogenates from controls, but partially reversed the diabetes-associated increase. Glucagon pretreatment of controls did not affect activity. In summary, distinct mitochondrial and cytosolic enzymes decarboxylate alpha-ketoisocaproate in liver. The increased hepatic capacity of diabetic rats to degrade the carbon skeleton of leucine is attributed mainly to a relative increase in mitochondrial mass.

MAPLE SYRUP URINE DISEASE: BRANCHED-CHAIN KETO-ACIDURIA

PEDIATRICS ◽  
1960 ◽  
Vol 25 (1) ◽  
pp. 72-79
Author(s):  
Joseph Dancis ◽  
Mortimer Levitz ◽  
Roland G. Westall
Keyword(s):  
Amino Acids ◽  
Maple Syrup Urine Disease ◽  
Animal Experiments ◽  
Oxidative Decarboxylation ◽  
Maple Syrup ◽  
Keto Acids ◽  
Metabolic Degradation ◽  
Urine Disease ◽  
Branched Chain ◽  
Derivatives Of

A case of maple syrup urine disease is presented. The patient lived for 20 months, the longest survival so far reported. There were increased amounts of leucine, isoleucine and valine in plasma and urine, indicating a block in the metabolic degradation of these amino acids. There was an accumulation in the urine of the respective keto acids, but not of the aldehydes or of the simple acids. This locates the block at a step common to all three amino acids, that of oxidative-decarboxylation. The alpha-hydroxy-acid derivatives of these amino acids are probably present, but the evidence is still incomplete. Animal experiments indicate that oxidative decarboxylation of the branched-chain amino acids is a metabolic step which is found generally in tissues, including leukocytes but probably not erythrocytes.

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