Methylcrotonoyl-CoA carboxylase beta chain (MCCC2)

Methylcrotonoyl-CoA carboxylase beta chain (MCCC2) is a mitochondrial enzyme that serves as the carboxyltransferase subunit of the 3-methylcrotonyl-CoA carboxylase (MCC) complex (Source: UniProt). This enzyme plays a vital role in the catabolism of the branched-chain amino acid leucine, specifically catalyzing the conversion of 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA (Source: Wikipedia). The MCC complex is a dodecamer consisting of six alpha subunits (MCCC1) and six beta subunits (MCCC2) (Source: NIH). Mutations in the MCCC2 gene lead to 3-methylcrotonyl-CoA carboxylase deficiency, one of the most common organic acidurias identified through newborn screening (Source: MedlinePlus). While many individuals with this deficiency remain asymptomatic, others may experience severe metabolic crises characterized by ketoacidosis, hypoglycemia, and neurological symptoms (Source: NIH). Therapeutic management typically involves biotin supplementation, L-carnitine to address secondary deficiency, and dietary leucine restriction (Source: Wikipedia). Beyond its metabolic role, recent studies have implicated MCCC2 in the progression of certain cancers, such as colorectal and breast cancer, where its overexpression is linked to increased cell proliferation and poor prognosis (Source: PubMed/NCBI). The enzyme is also regulated by SIRT4, which removes inhibitory acyl residues to maintain leucine catabolic flux (Source: Wikipedia).

Other names

MCCB3-methylcrotonyl-CoA carboxylase 23-methylcrotonyl-CoA carboxylase non-biotin-containing subunitMCCase subunit betaMethylcrotonoyl-CoA carboxylase subunit 23-methylcrotonyl-CoA:carbon dioxide ligase subunit beta

Cofactor supplementation to restore enzyme activity and metabolic detoxification via carnitine conjugation to facilitate excretion of toxic metabolites.