Anti-methylcrotonyl-CoA carboxylase subunit 2 antibodies are used for the immunodetection of the protein encoded by the MCCC2 gene. In humans, the canonical protein has a reported length of 563 amino acid residues and a mass of 61.3 kDa. Its subcellular localization is in the mitochondria. Alternative splicing is reported to yield 2 different isoforms for this protein. A member of the AccD/PCCB protein family, it is reported to be a carboxyltransferase subunit of the 3-methylcrotonyl-CoA carboxylase, an enzyme that catalyzes the conversion of 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA, a critical step for leucine and isovaleric acid catabolism. Other names for this target antigen include 3-methylcrotonyl-CoA carboxylase 2, 3-methylcrotonyl-CoA carboxylase non-biotin-containing subunit, 3-methylcrotonyl-CoA:carbon dioxide ligase subunit beta, and methylcrotonoyl-CoA carboxylase beta chain, mitochondrial. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.