methylmalonylKS

Methylmalonyl-CoA (MM-CoA) is an intermediate in the metabolism of odd-chain fatty acids and certain amino acids. It is derived from the breakdown of propionyl-CoA, which is produced from the metabolism of isoleucine, methionine, and valine. The conversion of propionyl-CoA to MM-CoA is catalyzed by the enzyme propionyl-CoA carboxylase (PCC), which requires biotin as a cofactor.

MM-CoA is then converted to succinyl-CoA, a key intermediate in the citric acid cycle (Krebs cycle), by the enzyme methylmalonyl-CoA mutase (MCM). MCM is a biotin-dependent enzyme that catalyzes the rearrangement of MM-CoA to succinyl-CoA. The activity of MCM is regulated by the availability of biotin and the concentration of MM-CoA.

Deficiencies in the enzymes involved in the metabolism of MM-CoA, such as PCC and MCM, can lead to metabolic disorders. For example, mutations in the MCM gene can cause methylmalonic acidemia (MMA), a rare inherited metabolic disorder characterized by the accumulation of methylmalonic acid in the blood and other tissues. MMA can lead to neurological symptoms, including seizures, developmental delays, and cognitive impairment.

In summary, methylmalonyl-CoA is a crucial intermediate in the metabolism of odd-chain fatty acids and certain amino acids. Its conversion to succinyl-CoA is catalyzed by the enzyme methylmalonyl-CoA mutase, which is regulated by the availability of biotin and the concentration of MM-CoA. Deficiencies in the enzymes involved in the metabolism of MM-CoA can lead to metabolic disorders, such as methylmalonic acidemia.