Adenosylcobalamin

Adenosylcobalamin, also known as coenzyme B12 or Adeno B12, is one of the two active coenzyme forms of vitamin B12 (cobalamin) in the human body, the other being methylcobalamin. As a vitamin, it is an essential micronutrient, meaning the body cannot produce it and it must be obtained through diet or supplementation. Adenosylcobalamin plays a critical role in cellular metabolism, particularly within the mitochondria, where it is vital for the proper function of the enzyme methylmalonyl-CoA mutase. This enzyme is involved in the catabolism of certain amino acids and odd-chain fatty acids, converting methylmalonyl-CoA to succinyl-CoA, a key intermediate in the citric acid cycle (Krebs cycle) for energy production. A deficiency in adenosylcobalamin or inherited defects in its metabolism can lead to the accumulation of methylmalonic acid in the body, which can have various metabolic and neurological consequences. Unlike cyanocobalamin, a synthetic form often used in supplements, adenosylcobalamin is a naturally occurring, biologically active form of vitamin B12.