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. 2015 Oct 7;5:14975. doi: 10.1038/srep14975

Figure 1. One of the possible pathways for chlorophyll biosynthesis in plants.

Figure 1

Reactions marked in red are the essential reactions (including transporters). For reactions numbered 1–15 refer Supplementary Figure S1 online. The three compartments, i.e. chloroplast, mitochondria and the cytosol were found to be involved in chlorophyll synthesis pathway. When Rubisco oxygenase activity comes into play, the peroxisome is also involved in the process, wherein a few of the photorespiratory reactions are also found to be essential. Bold purple arrow heads indicate the reactions involved when Rubisco carboxylase and oxygenase was set at 3:1, broken purple arrows indicate peroxisomal transporters. Methyl cycle is found to be essentially linked with chlorophyll synthesis. Intermediates: 3-P-HydP, 3-P-HYDROXYPYRUVATE; 3-P-Ser, 3-PHOSPHO-SERINE; HP, Hydrogen-peroxide; OH-Pyr, Hydroxy-pyruvate; 2OG, oxoglutarate; SAM, S-AdenosylMethionine; AdoHcy, AdenosylHomoCysteine; Hcy, homocysteine; Gly, glycine; AlphaKG , Alpha-ketoglutarate/oxoglutarate; Ser, serine; PEP, phosphoenol pyruvate; OAA, oxaloacetate; Mal, malate; Glu, glutamate; Gln, glutamine; Pyr,pyruvate; THF,tetrahydrofolate; MeTHF,5,10-methylenetetrahydrofolate; 5-MeTHF,5-methyltetrahydrofolate; MET,methionine. Enzymes of methyl cycle: 1, 5,10-methylenetetrahydrofolate:glycine hydroxymethyltransferase; 2, 5,10-methylenetetrahydrofolate reductase; 3, methionine synthase; 4, S-adenosylmethionine synthetase; 5, adenosylhomocysteinase. Enzymes: GS2, chloroplastic glutamine synthetase; GS1, cytosolic glutamine synthetase. External metabolites: x_CO2- external carbon-dioxide; x_Ammonia- external ammonia. _tx indicate the transporters. Reactions marked *are the reactions found to be essential but no supporting literature is available.