label: magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase activity
label_lc: magnesium-protoporphyrin ix monomethyl ester (oxidative) cyclase activity
description: "Catalysis of the reaction: magnesium protoporphyrin IX 13-monomethyl ester + 3 NADPH + 3 H+ + 3 O2 = divinylprotochlorophyllide + 3 NADP+ + 5 H2O."