Reactome: A Curated Pathway Database

Btn-ACACB:2Mn2+ polymer carboxylates Ac-CoA to form Mal-CoA

Stable Identifier
Homo sapiens
Locations in the PathwayBrowser

Mitochondrial acetyl-CoA carboxylase 2 (ACACB, ACC2) (Kim et al. 2007) catalyses the reaction of bicarbonate, ATP, and acetyl-CoA to form malonyl-CoA, ADP, and orthophosphate. The reaction is positively regulated by citrate. ACACB uses biotin (Btn) and two Mn2+ ions per subunit as cofactors and its activity is increased by polymerisation (Kim et al. 2010, Ingaramo & Beckett 2012). ACACB is located on the outer mitochondrial membrane and is involved in the regulation of mitochondrial fatty acid oxidation through the inhibition of carnitine palmitoyltransferase 1 by its product malonyl-CoA (Abu-Elheiga et al. 2000).

Mid1-interacting protein 1 (MID1IP1, aka MIG12, SPOT14R, S14R) plays a role in the regulation of lipogenesis in the liver. It is rapidly upregulated by processes that induce lipogenesis (enhanced glucose metabolism, thyroid hormone administration) (Tsatsos et al. 2008). MID1IP1 forms a heterodimer with thyroid hormone-inducible hepatic protein (THRSP, aka SPOT14, S14), proposed to play the same role in lipogenesis as MID1IP1 (Aipoalani et al. 2010). This complex can polymerise acetyl-CoA carboxylases 1 and 2 (ACACA and B), the first committed enzymes in fatty acid (FA) synthesis. Polymerisation enhances ACACA and ACACB enzyme activities (Kim et al. 2010).

Literature References
Participant Of
This entity is regulated by:
Title Physical Entity Activity
acetyl-CoA carboxylase activity of Btn-ACACB:2Mn2+ polymer [mitochondrial outer membrane] Btn-ACACB:2Mn2+ polymer [mitochondrial outer membrane] acetyl-CoA carboxylase activity (0003989)
Orthologous Events