Oxidative demethylation of algal carbohydrates by cytochrome P450 monooxygenases.

Sugar O-methylation shields algal polysaccharides against microbial hydrolytic enzymes. Here, we describe cytochrome P450 monooxygenases from marine bacteria that, together with appropriate redox-partner proteins, catalyze the oxidative demethylation of 6-O-methyl-D-galactose, which is an abundant monosaccharide of the algal polysaccharides agarose and porphyran. This previously unknown biological function extends the group of carbohydrate-active enzymes to include the class of cytochrome P450 monooxygenases.