label: erythromycin 3''-o-methyltransferase activity
label_lc: erythromycin 3''-o-methyltransferase activity
description: "Catalysis of the reaction: erythromycin C + S-adenosyl-L-methionine = erythromycin A + H+ + S-adenosyl-L-homocysteine. Also converts erythromycin D into erythromycin B."