Action of calcium ions on spinach (Spinacia oleracea) chloroplast fructose bisphosphatase and other enzymes of the Calvin cycle.
Thiol-treated spinach (Spinacia oleracea) chloroplast fructose bisphosphatase is powerfully inhibited by Ca2+ non-competitively with respect to its substrate, fructose 1,6-bisphosphate. 500 microM-Ca2+ causes virtually complete inhibition and the Ki is 40 microM. Severe inhibition of sedoheptulose bisphosphatase is also caused by Ca2+. A role for Ca2+ in regulation of the Calvin cycle in spinach chloroplasts is proposed.
D002118:Calcium / Q000494:pharmacology*; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology*; D004229:Dithiothreitol / Q000494:pharmacology; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology
D006597:Fructose-Bisphosphatase; D008274:Magnesium; D002118:Calcium; D004229:Dithiothreitol