The association of D-ribulose-1,5-bisphosphate carboxylase/oxygenase with phosphoribulokinase

• Published in: Plant physiology (Bethesda) Vol. 89; no. 1; pp. 368 - 374
• Main Authors: Sainis, J.K, Merriam, K, Harris, G.C
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-01-1989
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Analytical, structural and metabolic biochemistry; Antibodies; association; Biological and medical sciences; Chloroplasts; ELISA; Enzyme linked immunosorbent assay; Enzymes; Enzymes and enzyme inhibitors; ENZYMIC ACTIVITY; Fundamental and applied biological sciences. Psychology; LIASAS; LYASE; LYASES; Peas; Phosphates; phosphoribulokinase; PISUM SATIVUM; PLASTE; PLASTIDIOS; PLASTIDS; Quaternary ammonium compounds; ribulose-bisphosphate carboxylase; Spinach; SPINACIA OLERACEA; Sulfates; TEST ELISA; Time dependence; TRANSFERASAS; TRANSFERASE; TRANSFERASES; Phosphoribulokinase; Purification; Ribulosebisphosphate carboxylase; Enzyme; Dicotyledones; Angiospermae; Molecular association; Spermatophyta; Spinacia oleracea; ELISA assay; Chenopodiaceae
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.89.1.368

When Ribulose-1,5-bisphosphate carboxylase/oxygenase was purified from spinach leaves (Spinacia oleracea) using precipitation with polyethylene glycol and MgCl2 followed by DEAE cellulose chromatography, 75% of phosphoribulokinase and 7% of phosphoriboisomerase activities copurified with ribulose-1,5-bisphosphate carboxylase/oxygenase. This enzyme preparation showed ribose-5-phosphate and ribulose-5-phosphate dependent carboxylase and oxygenase activities which were nearly equivalent to its corresponding ribulose-1,5-bisphosphate dependent activity. The ribose-5-phosphate and ribulose-5-phosphate dependent reaction rates were stable and linear for much longer time periods than the ribulose-1,5-bisphosphate dependent rates. When sucrose gradients were used to purify ribulose-1,5-bisphosphate carboxylase/oxygenase from crude stromal extracts, phosphoribulokinase was found to cosediment with ribulose-1,5-bisphosphate carboxylase. Under these conditions most of the phosphoriboisomerase activity remained with the slower sedimenting proteins. Ammonium sulfate precipitation resulted in separation of the ribulose-1,5-bisphosphate carboxylase peak from phosphoribulokinase peak. Crude extracts of peas Pisum sativum and spinach contained 0.725 to 0.730 milligram of phosphoribulokinase per milligram of chlorophyll, respectively, based on an enzyme-linked immunosorbent assay.