In vitro characterization of a recombinant Blh protein from an uncultured marine bacterium as a beta-carotene 15,15'-dioxygenase.

ABSTRACT: Codon optimization was used to synthesize the blh gene from the uncultured marine bacterium 66A03 for expression in Escherichia coli. The expressed enzyme cleaved beta-carotene at its central double bond (15,15') to yield two molecules of all-trans-retinal. The molecular mass of the native purified enzyme was approximately 64 kDa as a dimer of 32-kDa subunits. The K(m), k(cat), and k(cat)/K(m) values for beta-carotene as substrate were 37 mum, 3.6 min(-1), and 97 mm(-1) min(-1), respectively. The enzyme exhibited the highest activity for beta-carotene, followed by beta-cryptoxanthin, beta-apo-4'-carotenal, alpha-carotene, and gamma-carotene in decreasing order, but not for beta-apo-8'-carotenal, beta-apo-12'-carotenal, lutein, zeaxanthin, or lycopene, suggesting that the presence of one un

SUBMITTER: Kim YS 

PROVIDER: S-EPMC2708875 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature