EC Number   |
General Information |
Reference |
|---|
    1.14.13.81 | metabolism |
in the chlorophyll biosynthesis pathway the formation of protochlorophyllide is catalyzed by Mg-protoporphyrin IX methyl ester (MgPME) cyclase. The requirement for de novo chlorophyll molecules differs completely for each chlorophyll-binding protein |
744998 |
| 1.14.13.81 | metabolism |
in the first unique step of the chlorophyll biosynthetic pathway, Mg2+ is inserted into protoporphyrin IX. Subsequently, a methyl group is transferred to the carboxyl group of the propionate on the C ring of Mg-protoporphyrin IX, generating Mg-protoporphyrin IX monomethyl ester (MPE), which is the substrate of the MPE cyclase. The cyclase catalyzes the formation of the isocyclic E ring by insertion of oxygen and attaching the methylated propionate to the methene bridge between pyrrole rings C and D, forming protochlorophyllide. Chlorophyll is obtained after additional reactions involving a light-dependent oxidation of protochlorophyllide to chlorophyllide, reduction of the vinyl group on the B ring, and, finally, addition of a polyisoprene tail |
765638 |
| 1.14.13.81 | metabolism |
magnesium-protoporphyrin IX monomethylester cyclase is one of the key enzymes of the bacteriochlorophyll biosynthesis pathway |
-, 726735 |
| 1.14.13.81 | metabolism |
Mg-protoporphyrin IX monomethyl ester cyclase (MPEC) plays an essential role in chlorophyll biosynthesis |
765584 |
| 1.14.13.81 | metabolism |
protochlorophyllide a production (formation of the isocyclic ring) via several intermediates in the chlorophyll biosynthesis pathway |
700629 |
| 1.14.13.81 | more |
protein YGL8 has the dual functions in chlorophyll biosynthesis: one as a catalytic subunit of MgPME cyclase, the other as a core component of FLU-YGL8-LCAA-POR complex in chlorophyll biosynthesis, physical interaction between YGL8 and a rice chloroplast protein, low chlorophyll accumulation A (OsLCAA). YGL8 also interacts with the other two rice chloroplast proteins, viz. fluorescent (OsFLU1) and NADPH:protochlorophyllide oxidoreductase (OsPORB) |
746095 |
| 1.14.13.81 | physiological function |
an essential enzyme during chlorophyll (Chl) biosynthesis. The enzyme subunit protein YL-1 is required for plastid membrane stability. The formation of the isocyclic ring is an aerobic reaction catalyzed by MPEC in chloroplasts, which controls the conversion of magnesium-protoporphyrin IX 13-monomethyl ester to divinyl protochlorophyllide (DVpchlide). The function of YL-1 in MPEC complex is essential for normal chlorophyll biosynthesis |
746223 |
| 1.14.13.81 | physiological function |
cyclic tetrapyrroles, are among the most abundant natural pigments on Earth. They are the major absorbers of the solar energy that drives photosynthesis, and billions of tonnes of chlorophyll are synthesised annually on land and in the oceans. The decisive biosynthetic step that determines the absorption properties of chlorophyll, and more visually its green color, is the formation of the unique isocyclic fifth ring. This process involves the conversion of Mg-protoporphyrin IX monomethyl ester (MgPME) to 3,8-divinyl protochlorophyllide a (DV PChlide a), and it requires incorporation of an oxygen atom, sourced from either water or O2, indicating the existence of two mechanistically different MgPME cyclases. Most anoxygenic phototrophic bacteria utilise an O2-sensitive radical SAM enzyme containing [4Fe-4S] and cobalamin cofactors to catalyse the reaction, while oxygenic phototrophs including cyanobacteria, algae and plants, as well as some purple bacteria, adopt an O2-dependent cyclase for the reaction. Mg-protoporphyrin IX monomethyl ester (MgPME) cyclase catalyses the formation of the isocyclic ring, the hallmark of chlorins and bacteriochlorins, producing protochlorophyllide a and contributing significantly to the absorption properties of chlorophylls and bacteriochlorophylls. The diiron cluster within AcsF is reduced by ferredoxin furnished by NADPH and ferredoxin:NADP+ reductase or by direct coupling to Photosystem I photochemistry, linking cyclase to the photosynthetic electron transport chain |
765462 |
| 1.14.13.81 | physiological function |
enzyme MPEC requires components found in both the membrane and soluble fractions of the chloroplast. It requires components associated with the plastid membrane and the plastid soluble fraction for activity. One of the components, XanL is found associated with the membrane and another protein, Ycf54 has been identified based upon its strong association of with XanL. The conserved chloroplast polypeptide Ycf54 is involved in the MPEC-enzyme catalyzed reaction |
744871 |
| 1.14.13.81 | physiological function |
Mg-protoporphyrin IX monomethyl ester cyclase (MPEC) plays an essential role in chlorophyll biosynthesis |
765584 |
