The Purification and Properties of Three Latter-Stage Enzymes of Chlorophyll Synthesis

Recent Progress in Porphyrin and Chlorophyll Biosynthesis

“…Other results, however, suggest that [3,8-DV]-PChlide is not the substrate of 8-vinyl group reduction: crude homogenates of etiolated wheat seedlings in the presence of NADH reduced only Mg-proto IX monomethylester and not Mg-[3,8-DV]-Pchlide (217). Later experiments with wheat etioplast preparations, however, showed that both substrates could be reduced and NADPH was the more effective cofactor (215). The detection of both the DV and MV forms of the 13'-hydroxy-, 13'-OXO-and 131-acrylate-derivatives of Mg-proto IX monomethylester in Chlorella mutants (199,200) is also consistent with the view that Mg-proto IX monomethylester can be a substrate of the 8-vinyl reductase.…”

“…It has been proposed (214) that 8-vinyl group reduction may occur at various stages of Chl biosynthesis between proto'gen IX and Chlide a; that is, several DV-and MV-Chl biosynthetic sequences may operate in parallel rather than the normally-accepted single linear pathway. The proportion of MV-and DV-Chls appears to be dependent on the plant examined and the light regime experienced during growth(215).The substrate of 8-vinyl group reduction is generally considered to be [3,8-DV]-PChlide because it accumulated in experiments with metabolic inhibitors…”