caa a22 4500 397520808 CHVBK 20180308164632.0 cr unu---uuuuu 161202e199508 xx s 000 0 eng 10.1093/jxb/46.8.1055 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.8.1055 The absence of Rubisco activase activity in total wheat leaf extracts is recovered in the purified protein [Elektronische Daten] [C.H. Foyer, M.A.J. Parry] When desalted extracts of soluble protein from dark-adapted wheat leaves were assayed for ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase activity in the presence of 1 mM ATP and an ATP-regenerating system, very little ATP-dependent activation of RuBP-inactivated Rubisco was found. In extracts from light-adapted leaves a very similar pattern of Rubisco activation was observed except that the overall level of Rubisco activity was much lower than in the extracts from dark-adapted leaves. These features were apparent both at low (120μg per ml) and high (640 μg per ml) protein concentrations. We were unable to demonstrate Rubisco activase activity in crude leaf extracts. Consequently, in order to establish that Rubisco activase was present in wheat leaf extracts the wheat leaf protein was purified to homogeneity. The identity of the protein was confirmed with antibodies to the spinach enzyme, ATPase activity and activase-mediated release of the inhibitor, carboxyara-binitol-1-phosphate (CA1P) from the tertiary Rubisco complex. The pure wheat Rubisco activase relieved the CA1P-induced inhibition of Rubisco activity. Rubisco activase had no significant effect on the affinity of wheat Rubisco for the substrate, ribulose-1, 5-bisphosphate (RuBP). © Oxford University Press Research Papers nationallicence Rubisco activase nationallicence Rubisco nationallicence regulation nationallicence Foyer C.H. Department of Environmental Biology IGER, Plas Gogerddan, Aberystwyth, Dyfed SY23 3EB, UK aut Parry M.A.J. Biochemistry and Physiology Department IACR-Rothamsted, Harpenden, Herts AL5 2JQ, UK aut Journal of Experimental Botany Oxford University Press 46/8(1995-08), 1055-1060 0022-0957 46:8<1055 1995 46 exbotj https://doi.org/10.1093/jxb/46.8.1055 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.8.1055 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Foyer C.H. Department of Environmental Biology IGER, Plas Gogerddan, Aberystwyth, Dyfed SY23 3EB, UK aut NATIONALLICENCE 700 1- Parry M.A.J. Biochemistry and Physiology Department IACR-Rothamsted, Harpenden, Herts AL5 2JQ, UK aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/8(1995-08), 1055-1060 0022-0957 46:8<1055 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford