Effects of carbon dioxide on mitochondrial enzymes from Ricinus

Abstract

Reactions of the Krebs cycle in a mitochondrial preparation from Ricinus endosperm have been studied in air and in CO2 concentrations up to 90%. Succinic oxidase is markedly inhibited in CO2 concentrations of 10% and above. At higher concentrations the conversion of pyruvate into cycle acids is also depressed, suggesting an inhibitory effect of CO2 on pyruvic oxidase or condensing enzyme. The results are discussed in relation to the effects of CO2 on intact plant tissues under aerobic conditions.