Molecular Aspects of Carotenoid Metabolizing Enzymes and Implications for Ophthalmology

Abstract Carotenoid metabolism plays a key role in human health and disease. Dietary ingestion does not reflect well the bioavailability of carotenoids in the human body that may be caused by the mutation, variant, and single-nucleotide polymorphisms in the two key carotenoid metabolizing enzymes, beta-carotene oxygenase 1 (BCO1) and beta-carotene oxygenase 2 (BCO2). In this chapter, we concisely review the recent progress in the regulation of carotenoid metabolism and absorption, colon microbiome, and molecular biology of the proteins. The potential implications of BCO1 and BCO2 for ophthalmology are further addressed. The nonenzymatic functions of these proteins in mitochondrial function, oxidaitve stress, inflammation, and visual health are also discussed.