This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Harris, G. C. Articles by Stern, A. I. Search for Related Content PubMed PubMed Citation Articles by Harris, G. C. Articles by Stern, A. I. Agricola Articles by Harris, G. C. Articles by Stern, A. I.

Articles

Isolation and Some Properties of Ribulose-1, 5-Bisphosphate Carboxylase-Oxygenase from Red Kidney Bean Primary Leaves ¹

^a Department of Botany, University of Massachusetts, Amherst, Massachusetts 01003

Purification of ribulose-1,5-bisphosphate carboxylase from primary leaves of Phaseolus vulgaris var. Red Kidney with ammonium sulfate precipitation, ion exchange chromatography, and gel filtration resulted in the complete loss of detectable oxygenase activity and the retention of a low velocity and a high K_m form of both the carboxylase and oxygenase. The polyethylene glycol-6000-purified ribulose-1, 5-bisphosphate oxygenase displayed a broad pH optimum (7.9-9.4) and a high K_m for O₂ and ribulose 1,5-bisphosphate (0.90 mM and 0.25 mM, respectively). Initiation of the oxygenase reaction with protein rather than ribulose 1,5-bisphosphate resulted in reduced activity. The enzymes prepared by the two purification procedures were electrophoretically different.

Etiolated primary leaf tissue exhibited low rates of both carboxylase and oxygenase. Similar developmental kinetic activity was observed for both reactions during greening. Photosynthetic ¹⁴CO₂ fixation was inhibited 95% by 100% N₂ gas during the first 24 hours of greening, but the inhibition was rapidly overcome by 48 to 72 hours of light exposure.

¹ The data are taken from a dissertation submitted by G. C. H. to the graduate faculty of the University of Massachusetts in partial fulfillment of the requirements for the Ph.D degree.