Propanoate metabolism

Propanoate metabolism is a fundamental biochemical pathway responsible for the breakdown of odd-chain fatty acids, the side chains of cholesterol, and specific branched-chain amino acids including isoleucine, valine, methionine, and threonine [KEGG map00640]. The pathway's primary function is the conversion of propionyl-CoA into succinyl-CoA, which subsequently enters the tricarboxylic acid (TCA) cycle to support cellular energy production [UniProt]. Key enzymes involved in this process include propionyl-CoA carboxylase (PCC) and methylmalonyl-CoA mutase (MCM), which require biotin and adenosylcobalamin (Vitamin B12) as essential cofactors, respectively [StatPearls]. Genetic deficiencies in these enzymes lead to severe metabolic disorders known as organic acidemias, specifically propionic acidemia and methylmalonic acidemia, characterized by the accumulation of neurotoxic metabolites [NIH/GARD]. Pharmacological intervention typically focuses on dietary restriction of precursor molecules and the administration of cofactors or carnitine to enhance metabolic flux and detoxification [PubMed, PMID: 24752367]. While not a single drug target itself, the individual enzymes and transporters within this pathway are critical focal points for therapeutic development and clinical management of inborn errors of metabolism.

Other names

Propionic acid metabolismPropionate pathwayMethylmalonate pathwayKEGG map00640

Therapeutic management of propanoate metabolism disorders involves the use of enzymatic cofactors such as biotin (for propionyl-CoA carboxylase) and vitamin B12 (for methylmalonyl-CoA mutase) to maximize residual enzyme activity [StatPearls, PMID: 29083611]. Levocarnitine is administered to facilitate the conversion of toxic propionyl-CoA into propionylcarnitine, which can be excreted in the urine [PubChem]. Additionally, carglumic acid may be used to treat secondary hyperammonemia by acting as a functional replacement for N-acetylglutamate to activate carbamoyl phosphate synthetase 1 [NIH/GARD].