PROSITE documentation PDOC50991

Pyruvate carboxyltransferase domain profile

Pyruvate carboxylase (EC 6.4.1.1) (PC), a member of the biotin-dependent enzyme family, is involved in the gluconeogenesis by mediating the carboxylation of pyruvate to oxaloacetate. Biotin-dependent carboxylase enzymes perform a two step reaction. Enzyme-bound biotin is first carboxylated by bicarbonate and ATP and the carboxyl group temporarily bound to biotin is subsequently transferred to an acceptor substrate such as pyruvate [1]. PC has three functional domains: a biotin carboxylase (BC) domain (see <PDOC50979>), a carboxyltransferase (CT) domain which perform the second part of the reaction and a biotinyl domain (see <PDOC50968>) [2,3]. The mechanism by which the carboxyl group is transferred from the carboxybiotin to the pyruvate is not well understood.

The pyruvate carboxyltransferase domain is also found in other pyruvate binding enzymes and acetyl-CoA dependent enzymes suggesting that this domain can be associated with different enzymatic activities:

• 2-isopropylmalate synthase (EC 2.3.3.13).
• (R)-citramalate synthase (EC 2.3.3.-).
• Homocitrate synthase (EC 2.3.3.14).
• Hydroxymethylglutaryl-CoA lyase (EC 4.1.3.4) (HMGL).
• 4-hydroxy-2-oxovalerate aldolase (EC 4.1.3.39) (HOA).
• Oxaloacetate decarboxylase (EC 4.1.1.3).

The profile we developed spans the entire carboxyltransferase domain.