4'-demethylrebeccamycin + S-adenosyl-L-methionine => rebeccamycin + S-adenosyl-L-homocysteine + H(+)
4'-demethylrebeccamycin + s-adenosyl-l-methionine => rebeccamycin + s-adenosyl-l-homocysteine + h(+)
4'-demethylrebeccamycin + S-adenosyl-L-methionine => rebeccamycin + S-adenosyl-L-homocysteine + H(+)
4'-demethylrebeccamycin + s-adenosyl-l-methionine => rebeccamycin + s-adenosyl-l-homocysteine + h(+)