FunctionSymmetrically cleaves beta-carotene into two molecules of retinal. The reaction proceeds in three stages, epoxidation of the 15,15'-double bond, hydration of the double bond leading to ring opening, and oxidative cleavage of the diol formed.
Tissue specificityHighly expressed in retinal pigment epithelium. Also expressed in kidney, testis, liver, brain, small intestine and colon.
PathwayCofactor metabolism; retinol metabolism.
Involvement in diseaseDefects in BCMO1 are the cause of autosomal dominant hypercarotenemia and vitamin A deficiency (ADHVAD) [MIM:115300]. Vitamin A is essential for normal embryonic development as well as normal physiological functions in children and adults. Hypercarotenemia is characterized by an excess carotene in the serum, but unlike excess vitamin A, carotene is non-toxic. So far, only a few cases of excess vitamin A have been reported. Individuals were thought to be vitamin A deficient due to an impairment in the conversion of carotenoids to retinal in the intestine.
Sequence similaritiesBelongs to the carotenoid oxygenase family.