ON THE BINDING OF SUCCINATE DEHYDROGENASE TO MITOCHONDRIAL INNER MEMBRANE
摘要
(1) The pH curve of the extraction of succinate dehydrogenase by butanol indicates that the binding of succinate dehydrogenase to the mitochondria has a pK value of 8 7. In extraction there is a critical butanol concentration of about 8% at 3℃. From the temperature curve of extraction it appears that the heats of activation which dissociate the binding of succinate dehydrogenase with the inner membrane will be quite low if the binding is through ionic bonds, and high if the binding is through hydrophobic bonds (over 26,000 cal. when temperature is above 11℃). The yields of extraction bear no linear relationship with the hydrocarbon chain length of the alcohol used.(2) Salts such as KCl and NaCl inhibit the reconstitution of soluble succinate dehydrogenase with alkali-treated heart muscle preparation. However, alcohols and non-ionic detergents promote reconstitution by 130%. Apart from this promoting effect they also markedly stimulate electron transfer from succinate dehydrogenase to cytochrome c in the reconstituted particles.(3) The inhibitory effect of TTFA on succinate-cytochrome c reductase activity in heart muscle preparation is influenced by the pH of the reaction medium. The plot of inhibitory percentages vs pHs indicates a pK value of 8.5 at 5～10℃.(4) Results from what have been discussed above suggest that succinate dehydrogenase binds to the mitochondrial inner membrane primarily through ionic bonds while hydrophobic bonds play a secondary role.