Comparison of response of succinic dehydrogenase and succinoxidase system to organic mercurial and thiol compounds.

Our earlier observations (l), extended in the present report, had indicated that the aerobic succinoxidase system was more sensitive to phenyhnercuric nitrate than the anaerobic succinic dehydrogenase system. Slater in a preliminary communication (2) called attention to a similar difference in sensitivity to p-chloromercuribenzoic acid. In studies of protection against mercurial inhibition by thiol compounds we noted the difference in response of the anaerobic and aerobic systems as well as the depressing effects of the thiols themselves on the aerobic system. Slater (3) and Barron et al. (4) meanwhile have reported similar effects for BAL and other dithiols. In addition we have noted an enhanced toxicity of cysteine and mercurial towards the aerobic system under certain conditions. Part of our results, although obtained independently and often with different compounds, are thus essentially confirmatory and will be presented only briefly.