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In enzymology, a glycerate dehydrogenase () is an enzyme that catalyzes the chemical reaction :(D)-glycerate + NAD+ hydroxypyruvate + NADH + H+ Thus, the two substrates of this enzyme are (R)-glycerate and NAD+, whereas its 3 products are hydroxypyruvate, NADH, and H+. However, in nature these enzymes have the ability to catalyze the reverse reaction as well. That is, hydroxypyruvate, NADH, and H+ can act as the substrates while (R)-glycerate and NAD+ are formed as products. Additionally, NADPH can take the place of NADH in this reaction. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (R)-glycerate:NAD+ oxidoreductase. Other names in common use include D-glycerate dehydrogenase, and hydroxypyruvate reductase (due to the reversibility of the reaction). This enzyme participates in glycine, serine and threonine metabolism and glyoxylate and dicarboxylate metabolism. == Enzyme Structure == This class of enzyme is part of a larger superfamily of enzymes known as D-2-hydroxy-acid dehydrogenases. Many organisms from ''Hyphomicrobium methylovorum'' to humans have some form of the glycerate dehydrogenase protein. There are currently several structures that have been solved for this class of enzyme including those for the two mentioned above with PDB access code , D-glycerate dehydrogenase, and the human homolog Glyoxylate Reductase/Hydroxypyruvate Reductase(GRHPR), . These studies have yielded a better understanding of the structure and function of these enzymes. It has been shown that that these proteins are homodimeric enzymes. This means that 2 identical proteins are linked forming one larger complex. The active sight is found in each subunit between the two distinct α/β/α globular domains, the substrate binding domain and the coenzyme binding domain.〔 This coenzyme binding domain is slightly larger than the substrate binding domain and contains a NAD(P) Rossman fold along with the "''dimerisation loop''" which holds the two subunits of the homodimer together.〔 In addition to linking the two proteins together, the "''dimerisation loop''" of each subunit protrudes into the active site of the other subunit increasing the specificity of the enzyme, by preventing the binding of pyruvate as a substrate. Hydroxypyruvate is still able to bind to the active site due to extra stabilization from hydrogen bonds with neighboring amino-acid residues.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glycerate dehydrogenase」の詳細全文を読む スポンサード リンク
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