Methylmalonsäure

Methylmalonic acid is a dicarboxylic acid with the chemical formula C4H6O4. It is an organic compound that plays a role in metabolism. Specifically, methylmalonic acid is an intermediate in the metabolism of certain amino acids, namely valine, isoleucine, threonine, and methionine. It is also involved in the breakdown of odd-chain fatty acids. The body typically converts methylmalonic acid into succinyl-CoA, which can then enter the citric acid cycle for energy production. This conversion is facilitated by an enzyme called methylmalonyl-CoA mutase, which requires vitamin B12 (cobalamin) as a cofactor.

Elevated levels of methylmalonic acid in the blood or urine can be an indicator of several medical conditions. A deficiency in vitamin B12 is a common cause of increased methylmalonic acid. This deficiency impairs the function of methylmalonyl-CoA mutase, leading to a buildup of the acid. Other causes of elevated methylmalonic acid include certain genetic disorders, such as methylmalonic acidemia, which are rare inherited metabolic diseases affecting the enzyme responsible for methylmalonic acid metabolism. It can also be seen in individuals with propionic acidemia or methylmalonic aciduria, other inherited metabolic disorders. Measuring methylmalonic acid levels is a useful diagnostic tool for identifying vitamin B12 deficiency and certain inborn errors of metabolism.