Reversible Phosphorylation in the Regulation of Photosynthetic Phosphoenolpyruvate Carboxylase in C4 Plants

摘要: C4 species have a specific isoform of phosphoenolpyruvate Carboxylase (PEPC) that catalyzes primary CO2 fixation in the photosynthesis pathway. It has long been known enzyme cytosol mesophyll cells is subject to allosteric control by opposing photosynthesis-related metabolites. The discovery phosphorylation process acting on PEPC, via complex light-signal transduction cascade, revitalized interest this and ensuing wealth data highlighted one few signaling cascades so far regulation plant metabolism. cascade depends upon cross-talk between two neighboring photosynthetic cell types, involves classical second messengers like pH, Inosital-1,4 5-trisphosphate (Ins(1,4,5) P3) calcium, upregulates activity Ca2+-independent, PEPC-specific protein-serine/threonine kinase, which finally phosphorylates PEPC. final PEPC resulting carbon flux bundle sheath are dependent mutual interaction metabolite covalent mechanisms enzyme.