INHIBITION or SUCCINATE DEHYDROGENASE 



47 



Table 1-9 



Effect of Osmolarity in the Properties of Succinate Oxidase in Lupine 



Mitochondria " 



" Kj„ is the Michaelis constant for succinate, iT, the inhibitor constant for malonate, 

 and a is the interaction constant defined in Eqs. 1-3-5 and 1-3-6, indicating the type 

 of inhibition. The osmolarity is given in terms of sucrose concentration. (From Honda 

 and Muenster, 1961.) 



of Ca'^^ concentration on both succinate oxidation and malonate inhibition 

 are complex (Fig. 1-9) and difficult to explain. The decrease in the rate 

 of oxidation beyond Ca+"^ concentrations around 5 m.M might be attributed 

 to a complexing of the succinate, but for the same reason, namely, the 

 complexing of malonate, which has a higher affinity for Ca+''" than does 

 succinate, the inhibition would be expected to decrease. Whether the 



0.001 01 



Fig. 1-9. Effects of Ca++ on the rate of succinate oxidation and 

 the inhibition by malonate in rat heart mitochondria. Succinate is 

 5 mM and malonate is 1 mM. (From Montgomery and Webb, 1956 b). 



