title: Isozymes of phosphoglyceromutase from the developing endosperm of Ricinus communis: isolation and kinetic properties.
abstract: The isozymes of phosphoglyceromutase from the developing endosperm of Ricinus communis have been partially purified. The purified cytosolic and plastid isozymes have specific activities of 622.8 and 83.8 mumol min-1 mg protein-1, respectively. They both have relative molecular masses of approximately 64,000. The cytosolic enzyme has lower Km values for both 2-phosphoglycerate and 3-phosphoglycerate than the plastid enzyme. The Km values for 3-phosphoglycerate are 330 +/- 25 and 430 +/- 48 microM for the cytosolic and plastid isozymes, respectively. The corresponding Km values for 2-phosphoglycerate are 60 +/- 10 and 112 +/- 22 microM. The two isozymes also have different pH optima and heat labilities. Neither isozyme requires 2,3-bisphosphoglycerate or a divalent cation and neither is regulated by metabolites.
mesh_terms: D003600:Cytosol / Q000201:enzymology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000302:isolation & purification*; D007700:Kinetics; D008970:Molecular Weight; D010736:Phosphoglycerate Mutase / Q000302:isolation & purification*; D010770:Phosphotransferases / Q000302:isolation & purification*; D010947:Plants, Toxic; D012278:Ricinus / Q000201:enzymology* / Q000254:growth & development
chemical_list: D007527:Isoenzymes; D010770:Phosphotransferases; D010736:Phosphoglycerate Mutase