ENZYME entry: EC 1.2.4.4

Accepted Name
3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring).
Alternative Name(s)
2-oxoisocaproate dehydrogenase.
2-oxoisovalerate (lipoate) dehydrogenase.
3-methyl-2-oxobutanoate dehydrogenase (lipoamide).
3-methyl-2-oxobutanoate:lipoamide oxidoreductase (decarboxylating and acceptor-2-methylpropanoylating).
Alpha-keto-alpha-methylvalerate dehydrogenase.
Alpha-ketoisocaproate dehydrogenase.
Alpha-ketoisocaproic dehydrogenase.
Alpha-ketoisocaproic-alpha-keto-alpha-methylvaleric dehydrogenase.
Alpha-ketoisovalerate dehydrogenase.
Alpha-oxoisocaproate dehydrogenase.
BCKDH.
BCOAD.
Branched chain keto acid dehydrogenase.
Branched-chain (-2-oxoacid) dehydrogenase (BCD).
Branched-chain 2-keto acid dehydrogenase.
Branched-chain 2-oxo acid dehydrogenase.
Branched-chain alpha-keto acid dehydrogenase.
Branched-chain alpha-oxo acid dehydrogenase.
Branched-chain keto acid dehydrogenase.
Branched-chain ketoacid dehydrogenase.
Dehydrogenase, 2-oxoisovalerate (lipoate).
Dehydrogenase, branched chain alpha-keto acid.
Reaction catalysed
3-methyl-2-oxobutanoate + [dihydrolipoyllysine-residue (2-methylpropanoyl)transferase] lipoyllysine <=> [dihydrolipoyllysine-residue (2-methylpropanoyl)transferase] S-(2-methylpropanoyl)dihydrolipoyllysine + CO(2)
Cofactor(s)
Thiamine diphosphate.
Comment(s)
  • It acts not only on 3-methyl-2-oxobutanaoate, but also on 4-methyl-2- oxopentanoate and (S)-3-methyl-2-oxopentanoate, so that it acts on the 2-oxo acids that derive from the action of transaminases on valine, leucine and isoleucine.
  • It is a component of the multienzyme 3-methyl-2-oxobutanoate dehydrogenase complex in which multiple copies of it are bound to a core of molecules of EC 2.3.1.168, which also binds multiple copies of EC 1.8.1.4.
  • It does not act on free lipoamide or lipoyllysine, but only on the lipoyllysine residue in EC 2.3.1.168.
  • Formerly EC 1.2.4.3.
Cross-references
BRENDA1.2.4.4
EC2PDB1.2.4.4
ExplorEnz1.2.4.4
PRIAM enzyme-specific profiles1.2.4.4
KEGG Ligand Database for Enzyme Nomenclature1.2.4.4
IUBMB Enzyme Nomenclature1.2.4.4
IntEnz1.2.4.4
MEDLINEFind literature relating to 1.2.4.4
MetaCyc1.2.4.4
UniProtKB/Swiss-Prot
P9WIS2, BKDA_MYCTO;  P9WIS3, BKDA_MYCTU;  P9WIS0, BKDB_MYCTO;  
P9WIS1, BKDB_MYCTU;  Q9LPL5, ODBA1_ARATH;  Q84JL2, ODBA2_ARATH;  
P37940, ODBA_BACSU;  P11178, ODBA_BOVIN;  O45924, ODBA_CAEEL;  
Q54M22, ODBA_DICDI;  P12694, ODBA_HUMAN;  Q8HXY4, ODBA_MACFA;  
P50136, ODBA_MOUSE;  A5A6H9, ODBA_PANTR;  Q9I1M2, ODBA_PSEAE;  
P09060, ODBA_PSEPU;  P11960, ODBA_RAT;  Q72GU1, ODBA_THET2;  
Q5SLR4, ODBA_THET8;  Q9SAV3, ODBB1_ARATH;  Q9LDY2, ODBB2_ARATH;  
P37941, ODBB_BACSU;  P21839, ODBB_BOVIN;  Q55FN7, ODBB_DICDI;  
P21953, ODBB_HUMAN;  Q6P3A8, ODBB_MOUSE;  Q9I1M1, ODBB_PSEAE;  
P09061, ODBB_PSEPU;  P35738, ODBB_RAT;  Q72GU2, ODBB_THET2;  
Q5SLR3, ODBB_THET8;  

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