Studies on the Action of Sulfonamides on the Respiration and Growth of Bacteria

Abstract

Sulfathiazole inhibits the carboxylase activity of whole yeast. It is shown that one molecule of cocarboxylase added to the reaction system is capable of counteracting the inhibitory effect of 8,088 to 53,400 molecules of sulfathiazole. Washing yeast cells with alkaline phosphate removes practically all of the carboxylase activity. Addition of cocarboxylase restores 56-76% of the original activity. Under these conditions sulfathiazole and cocarboxylase compete for the specific carboxylase protein. This competition results in the neutralization of the inhibition by sulfathiazole. One molecule of cocarboxylase counteracts the inhibition exercised by 322-646 molelcules of sulfathiazole. Sulfathiazole inhibits the carboxylase activity of Staphylococcus aureus. One molecule of cocarboxylase counteracts the inhibitory effect of 215 molecules of sulfathiazole. Staphylococci when grown in glucose phosphate extract broth have been found to be devoid of carboxylase activity. Staphylococci when grown in glucose-free plain extract broth have been found to manifest good carboxylase activity. The reason for this is not known.