The effect of SO3--on the activity of ribulose-1,5-diphosphate carboxylase in isolated spinach chloroplasts

摘要

SO3--inhibits the activity of ribulose-1,5-diphosphate carboxylase in isolated spinach chloroplasts. It shows a non-competitive inhibition pattern with respect to ribulose-1,5-diphosphate and Mg++but a competitive one with respect to HCO3-. TheKi-values are 14 mM SO3--and 9.5 mM SO3-respectively for the non-competitive inhibition but only 3.0 mM SO3--in the case of competitive inhibition with HCO3--as a substrate. Thus it is concluded that the competitive inhibition type will predominate at low SO3--and low internal CO2concentrations.