Dehydrogenases


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Dehydrogenases

 

enzymes that catalyze the removal of hydrogen from organic compounds. The coenzymes of dehydrogenases are usually dinucleotides: nicotinamide adenine dinucleotide (NAD), nicotinamide adenine dinucleotide phosphate (NADP), or flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), which accept hydrogen from the oxidizable substance. Dehydrogenases bring about the first stage of biological oxidation and play a large part in the Krebs cycle, glycolysis, and the pentose phosphate cycle. In the organism the NADP, reduced through the action of certain dehydrogenases, is used to synthesize fatty acids. Some dehydrogenases, unconnected with coenzymes, catalyze the direct oxidation of substances by oxygen. Many dehydrogenases contain metals (zinc or manganese) that are part of their active centers.

G. Z. SOLOV’EVA

References in periodicals archive ?
In the sulfite oxidases, the pyranopterin was always very flat, whereas in the xanthine dehydrogenases, it's skewed.
Table 1 Kinetic Constants for Ethanol Oxidation by Human Alcohol Dehydrogenases (1) [K.
Changes in testicular lactate dehydrogenases of the rat (Rattus norvegicus) during growth and development.
Alcohol dehydrogenases make up one of the important enzyme classes in this field and can be used for the cost efficient synthesis of chiral alcohols from ketones with extraordinary purities.
It is known that alcohol dehydrogenase (ALD)-based ethanol assays that quantify NADH (or an NADH analog, in this case) spectrophotometrically can produce spuriously increased results in the presence of high concentrations of lactate dehydrogenase (LDH) and lactate (2, 3).
Amino acid sequence comparisons show the class I and class III human alcohol dehydrogenases share 59% amino acid identity and 72% amino acid similarity.
The primary enzymes involved in alcohol metabolism are alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH).
Deficiencies of NADH and succinate dehydrogenases in degenerative diseases and myopathies.
To determine how the enzyme maintains its speed, the researchers examined differences between the sequences of amino acids that make up lactate dehydrogenases in the different fish.
Based on the biochemical analysis the authors propose the mode of action of EGME-induced toxicity is mediated through the inhibition of primary flavoprotein dehydrogenases.
This is in contrast to the situation for human very long-chain, long-chain, and medium-chain acyl-CoA dehydrogenases, which are stereospecific for the S-enantiomers only of their methyl branched-chain substrates (24).
In addition, the amino acid sequences in the two versions look alike, even though they do not match those of longer, more intensively studied dehydrogenases containing 350 amino acids.