Effects of Photosynthetic Intermediates on the Activation State of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from Euglena gracilis Z(Biological Chemistry)

概要

論文の詳細を見る
The half-saturating concentration of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) from Euglena gracilis Z for CO_2 in its activation by CO_2 in the presence of a saturating concentration of MgCl_2 (K_a) was measured by analyzing the partial reversible inactivation of the fully activated enzyme in the medium with dilute CO_2. The K_a of the Euglena enzyme was 12.5μM. The K_a values were 6.3μM for the enzyme from soybean, 10.8μM from maize, 23.3μM from Scenedesmus obliquus, and 20.8μM from Anabaena 7120. The activated state of Euglena RuBisCO was stabilized by 6-phosphogluconate, fructose 1,6-bisphosphate, and 3-phosphoglycerate in the medium containing low concentrations of CO_2. Both fructose 6-phosphate and ATP stimulated inactivation in the medium. NADPH not only stabilized the activated state of the enzyme, but also enhanced the enzyme activity over the full activity measured in the absence of NADPH. NADP^+ did not nullify the effects of NADPH on the activation at all. The physiological significance of the effects of these photosynthetic metabolites on the activated state of Euglena RuBisCO is discussed.
社団法人日本農芸化学会の論文
1989-08-23