What is "hydroxocobalamin"

n. (context biochemistry English) A natural analogue of vitamin B12, a basic member of the cobalamin family of compounds, with an intense red colour.

Hydroxocobalamin (also hydroxycobalamin, OHCbl, or B) is a natural form, or vitamer, of vitamin B. It is a member of the cobalamin family of compounds. Hydroxocobalamin is produced by many bacteria that are used to produce the vitamin commercially. Like other forms of vitamin B, hydroxocobalamin has an intense red color. In humans, it is rapidly converted to usable coenzyme forms of vitamin B. Hydroxocobalamin is used as an injectable solution for treatment of the vitamin deficiency and for treatment for cyanide poisoning. It has been tested as a scavenger of nitric oxide.

"Vitamin B" refers to a group of compounds called cobalamins that are available in the human body in a variety of mostly interconvertible forms. Together with folate, cobalamins are essential cofactors required for DNA synthesis in cells where chromosomal replication and division are occurring—most notably the bone marrow and myeloid cells. As a cofactor, cobalamins are essential for two cellular reactions:

• the mitochondrial methylmalonyl-CoA mutase conversion of methylmalonic acid (MMA) to succinate, which links lipid and carbohydrate metabolism, and
• the activation of methionine synthase, which is the rate-limiting step in the synthesis of methionine from homocysteine and 5-methyltetrahydrofolate.

It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.