An efficient method for the determination of Km values for HCO3- of phosphoenolpyruvate carboxylase
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- Bauwe, H. Planta (1986) 169: 356. doi:10.1007/BF00392131
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One of the most serious problems in obtaining estimates of the Km values for HCO3-of phosphoenolpyruvate carboxylase (PEPCase; EC 18.104.22.168) 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-/CO2 contamination. The kinetic data are obtained by the evaluation of progress curves of HCO3-consumption. The method is discussed and the Km values for HCO3-of PEPCase from several C4-species are presented.
Key wordsC4-species (PEPCase)Kinetic properties (PEPCase)Phosphoenolpyruvate carboxylase
- C3, C4
assimilated CO2 initially found in 3-phosphoglycerate (C3) or malate and aspartate (C4)