Oxygen Inhibition and Other Properties of Soybean Ribulose 1,5-Diphosphate Carboxylase

Abstract

n-Ribulose-l , 5-di-P carboxylase, purified from soybeans, had K, values of 0.13 XnM for COS and 0.19 mM for ribulose-1,5-di-P under a Nz atmosphere.O2 inhibited 14C02 incorporation by the enzyme and this inhibition was rapidly reversed by Ns.Inhibition was competitive with respect to CO2 and uncompetitive with respect to ribulose-1,5-di-P.The Ki for O2 was 0.8 mM.This O2 inhibition, together with the ribulose-1,5-di-P carboxylase-catalyzed oxidation of ribulose-l ,5