catalytic complex methylcrotonoyl-CoA carboxylase complex https://github.com/geneontology/go-ontology/issues/28023 cellular_component GO:1905202 bf A protein complex capable of methylcrotonoyl-CoA carboxylase activity. In mammals, it is a mitochondrial complex comprising a dodecamer of 6 alpha and 6 beta subunits: MCCC-alpha has a covalently bound biotin essential for the ATP-dependent carboxylation; MCCC-beta possesses carboxyltransferase activity which presumably is essential for binding to 3-methylcrotonyl-CoA. 2016-05-16T11:03:20Z