27-O-demethylrifamycin SV + S-adenosyl-L-methionine <=> rifamycin SV + S-adenosyl-L-homocysteine + H(+)
27-o-demethylrifamycin sv + s-adenosyl-l-methionine <=> rifamycin sv + s-adenosyl-l-homocysteine + h(+)