1.3.1.33 chlorophyllide a + NADP+ - 1.3.1.33 chlorophyllide a + NADP+ POR catalyzes the NADPH-dependent reduction of the C17-C18 double bond of protochlorophyllide to form chlorophyllide 1.3.1.33 divinyl protochlorophyllide a + NADPH - 1.3.1.33 monovinyl protochlorophyllide a + NADPH - 1.3.1.33 additional information - 1.3.1.33 additional information does not accept protochlorophyllide a' or any other compounds with substituents at C-13-2 different from protochlorophyllide a 1.3.1.33 additional information naturally occurring esterified protochlorophyllide and chemically prepared protochlorophyllide methyl ester are not substrates for the enzyme, removal of Mg2+ from the protochlorophyllide leads to inactivity of the compound as a substrate 1.3.1.33 additional information the inhibition of por gene expression by continous far red light is mediated by phytochrome A 1.3.1.33 protochlorophyllide + NADH + H+ - 1.3.1.33 protochlorophyllide + NADPH -