An efficient method for the determination ofKmvalues for HCO3-of phosphoenolpyruvate carboxylase

摘要

One of the most serious problems in obtaining estimates of theKmvalues for HCO3-of phosphoenolpyruvate carboxylase (PEPCase; EC 4.1.1.31) by measurement of initial rates at varying HCO3-is the impossibility of completely excluding any contaminating HCO3-. A method is proposed which has no need for the careful control of HCO3-/CO2contamination. The kinetic data are obtained by the evaluation of progress curves of HCO3-consumption. The method is discussed and theKmvalues for HCO3-of PEPCase from several C4-species are presented.