Beta-carotene 15,15'-monooxygenase 1 (BCO1)

Beta-carotene 15,15'-monooxygenase 1 (BCO1) is a critical enzyme in human nutrition, serving as the primary catalyst for the conversion of dietary provitamin A carotenoids, such as beta-carotene, into retinal (UniProt Q9HAY6). This symmetrical oxidative cleavage occurs predominantly in the intestinal mucosa and liver, providing the essential precursor for all retinoids required for vision, immune function, and cellular differentiation (GeneCards BCO1). Genetic polymorphisms in the BCO1 gene, such as rs12934922 and rs7501331, are highly prevalent and significantly impair enzymatic activity, leading to substantial interindividual variability in Vitamin A status (PMID: 19103647, 27511934). Beyond its classical role in Vitamin A synthesis, BCO1 is increasingly recognized for its involvement in lipid metabolism, where it modulates cholesterol transport and influences the development of atherosclerosis and metabolic syndrome (PMID: 33166345). Therapeutic interventions often target the BCO1 pathway by either supplementing with its substrate, beta-carotene, or bypassing the enzyme with preformed retinol in individuals with genetic bottlenecks (PMID: 27511934). However, pharmacological modulation must be approached with caution, as high-dose beta-carotene has been associated with increased lung cancer risk in smokers, and excessive preformed Vitamin A can lead to toxicity (PMID: 8127329).

Other names

BCMO1BCDO1BCMOBCDOBeta-carotene dioxygenase 1Beta-carotene oxygenase 1Beta,beta-carotene 15,15'-monooxygenase

BCO1 catalyzes the symmetrical oxidative cleavage of beta-carotene at the 15,15' double bond to produce two molecules of retinal, which are subsequently converted to retinol or retinoic acid (UniProt Q9HAY6). Its expression is transcriptionally regulated by nuclear receptors including PPARgamma and RXR, and can be inhibited by PPARalpha activation or glucocorticoid signaling (PMID: 28732066).