Oxidative cleavage of carotenoids catalyzed by enzyme models and beta-carotene 15,15´-monooxygenase

Abstract

The enzyme that catalyzes the central cleavage of β-carotene is an iron monooxygenase. The protein was isolated from chicken intestinal mucosa and overexpressed in two different cell lines. Inductively coupled plasma (ICP) emission analysis revealed that the hydrophobic 60.3-kDa enzyme contains one iron/mole protein. The substrate specificity was investigated, and the reaction mechanism elucidated incubating α-carotene in the presence of highly enriched 17O2 and H218O. A supramolecular enzyme model was synthesized, binding carotenoids Ka > 106 mol-1, which mimics the regiospecific enzymatic cleavage of carotenoids.