HMM Summary Page: TIGR00175

Functionisocitrate dehydrogenase, NAD-dependent
Trusted Cutoff432.40
Domain Trusted Cutoff432.40
Noise Cutoff323.75
Domain Noise Cutoff323.75
Isology Typeequivalog
EC Number1.1.1.41
HMM Length334
Mainrole CategoryEnergy metabolism
Subrole CategoryTCA cycle
Gene Ontology TermGO:0004449: isocitrate dehydrogenase (NAD+) activity molecular_function
GO:0005962: mitochondrial isocitrate dehydrogenase complex (NAD+) cellular_component
GO:0006102: isocitrate metabolic process biological_process
GO:0045243: cytosolic isocitrate dehydrogenase complex (NAD+) cellular_component
AuthorHaft DH
Entry DateApr 20 1999 2:08PM
Last ModifiedFeb 14 2011 3:27PM
CommentSeveral NAD- or NADP-dependent dehydrogenases, including 3-isopropylmalate dehydrogenase, tartrate dehydrogenase, and the multimeric forms of isocitrate dehydrogenase, share a nucleotide binding domain unrelated to that of lactate dehydrogenase and its homologs. These enzymes dehydrogenate their substates at a H-C-OH site adjacent to a H-C-COOH site; the latter carbon, now adjacent to a carbonyl group, readily decarboxylates. Mitochondrial NAD-dependent isocitrate dehydrogenases (IDH) resemble prokaryotic NADP-dependent IDH and 3-isopropylmalate dehydrogenase (an NAD-dependent enzyme) more closely than they resemble eukaryotic NADP-dependent IDH. The mitochondrial NAD-dependent isocitrate dehydrogenase is believed to be an alpha(2)-beta-gamma heterotetramer. All subunits are homologous and found by this model. The NADP-dependent IDH of Thermus aquaticus thermophilus strain HB8 resembles these NAD-dependent IDH, except for the residues involved in cofactor specificity, much more closely than it resembles other prokaryotic NADP-dependent IDH, including that of Thermus aquaticus strain YT1.
ReferencesA2 hmmalign SE TIGR GA hmmls AL clustalw BD build_dir/0253
Genome PropertyGenProp0033: TCA cycle (HMM)