This family consists of several eukaryotic malonyl-CoA decarboxylase (MLYCD) proteins. Malonyl-CoA, in addition to being an intermediate in the de novo synthesis of fatty acids, is an inhibitor of carnitine palmitoyltransferase I, the enzyme that regulates the transfer of long-chain fatty acyl-CoA into mitochondria, where they are oxidised. After exercise, malonyl-CoA decarboxylase participates with acetyl-CoA carboxylase in regulating the concentration of malonyl-CoA in liver and adipose tissue, as well as in muscle. Malonyl-CoA decarboxylase is regulated by AMP-activated protein kinase (AMPK) [1].

1: Coordinate regulation of malonyl-CoA decarboxylase, sn-glycerol-3-phosphate acyltransferase, and acetyl-CoA carboxylase by AMP-activated protein kinase in rat tissues in response to exercise. Park H, Kaushik VK, Constant S, Prentki M, Przybytkowski E, Ruderman NB, Saha AK; J Biol Chem 2002;277:32571-32577. PMID:12065578