Abstract
S-oxygenation of S-allyl-L-cysteine (SAC) is the last step of alliin biosynthesis. The degradation of alliin produces various organosulfur compounds, which show antimicrobial and anticancer properties. In Arabidopsis thaliana, the S-oxygenation of glucosinolates is catalyzed by flavin-containing monooxygenases (FMOs). Under the assumption that SAC is S-oxygenated by FMOs, we cloned the FMO-like gene (AsFMO1) from garlic by using the primers designed from FMO-like EST sequences of onion. We conducted RT-PCR and 5'/3'-RACE using RNA extracted from a garlic as a template. The ORF of AsFMO1 encodes 457 amino acids containing FAD-binding motif and NADP-binding motif, which are essential for FMO activity. AsFMO1 showed 51-55% identities with FMOs, which catalyze S-oxygenation of glucosinolates in A.thaliana. The functional analysis of AsFMO1 recombinant protein expressed in Escherichia coli is in progress.
