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Molecular hybridization of Rubisco subunits between rice and tobacco

Miao Yougang, Li Liren

Shanghai Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghai 200032

Abstract

Both homogenous and hetero genous molecular hybridizations between large and small subunits were performed after dissociation of immobilized Rubisco from tobacco or rice at 2. 5 mol/L urea. The results showed that homogenous and heterogenous hybidizations led to similar recovery of caboxylase activity,but much different recovery in oxygenase activity. The oxygenase activity of heterogenous hybrid enzyme between immobilized large subunit from rice and free small subunit from tobacco was found to be higher than that of homogenous recontituted enzyme from rice, so that its ratio of carboxylase to oxygenase was lower than that of homogenous reconstituted enzyme and similar to that of undissociated immobile Rubisco from tobacco. On the other hand, in the case of the immobilized large subunit from tobacco hybridized with free small subunit from rice, its ratio of carboxylase to oxygenase is higher than that of homogenous reconstituted enzyme due to the red uction of oxygenase activity, and also similar to that of the undissociated immobile Rubisco from rice. Therefore, it is suggested that the function of Rubisco small subunts may be involved in the oxygenase activity, which resuts in a change of the carboxylation/oxygenation ratio of Rubisco.

Key words: Rubisco;Rice;Tobacco;Molecular hybridization;Ratio of carboxylase/oxygenase (C/O)

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Citing This Article：

Miao Yougang, Li Liren. Molecular hybridization of Rubisco subunits between rice and tobacco. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).