title: Phosphorylation in vitro of the large subunit of the ribulose-1,5-bisphosphate carboxylase and of the glyceraldehyde-3-phosphate dehydrogenase.
abstract: A protein kinase activity responsible for the in vitro phosphorylation of at least six endogenous polypeptides including the large subunit of the ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) is present in the stroma (3000 X g supernatant, S30) of spinach chloroplasts. The phosphorylation of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit is strongly enhanced when sodium fluorure is used as a protein phosphatase inhibitor. Phosphorylation occurs on threonine and serine residues. The protein kinase involved is not Ca2+-dependent. There is also evidence for a protein phosphatase activity which suggests a coupled regulation by a phosphorylation-dephosphorylation process. The phosphorylating activity is drastically reduced when S30 is prepared from leaves harvested after a dark period. Phosphorylation of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit is not related to its own synthesis. The in vitro phosphorylation of the glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13) is also demonstrated.
mesh_terms: D002736:Chloroplasts / Q000201:enzymology; D003624:Darkness; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D008027:Light; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000096:biosynthesis; D010944:Plants / Q000201:enzymology*; D011494:Protein Kinases / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D011494:Protein Kinases; D010744:Phosphoric Monoester Hydrolases; D012273:Ribulose-Bisphosphate Carboxylase