标题：Amino acid sequence homology among the 2-hydroxy acid dehydrogenases: mitochondrial and cytoplasmic malate dehydrogenases form a homologous system with lactate dehydrogenase
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：20
页码：6166-6170
DOI：10.1073/pnas.79.20.6166
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The amino acid sequence of porcine heart mitochondrial malate dehydrogenase (mMDH; L-malate: NAD+ oxidoreductase, EC 1.1.1.37 ) has been compared with the sequences of six different lactate dehydrogenases (LDH; L-lactate: NAD+ oxidoreductase, EC 1.1.1.27 ) and with the "x-ray" sequence of cytoplasmic malate dehydrogenase (sMDH). The main points are that (i) all three enzymes are homologous; (ii) invariant residues in the catalytic center of these enzymes include a histidine and an internally located aspartate that function as a proton relay system; (iii) numerous residues important to coenzyme binding are conserved, including several glycines and charged residues; and (iv) amino acid side chains present in the subunit interface common to the MDHs and LDHs appear to be better conserved than those in the protein interior. It is concluded that LDH, sMDH, and mMDH are derived from a common ancestral gene and probably have similar catalytic mechanisms.
