The enzyme, characterized from the bacterium Bacillus thuringiensis, can also catalyse the hydroxylation of L-leucine, L-norvaline, L-norleucine, and L-allo-isoleucine, as well as the sulfoxidation of L-methionine, L-ethionine, S-methyl-L-cysteine, S-ethyl-L-cysteine, and S-allyl-L-cysteine.