Inhibition steps in sulphonamide bacteriostasis

Abstract

The activity of several compounds, structurally unrelated to p-aminobenzoic acid, in reversing growth inhibition of Escherichia coli by sulphonamides, was explained by Shive and Roberts as due to their being products of enzymes associated with p-amino-benzoic acid. Using increasing concentrations of sulphanilamide, these authors showed that it inhibits sequentially the synthesis of methionine and xanthine by the organism. Winkler and de Haan extended this study to higher concentrations of the inhibitor, and reported further involvement of serine and thymine (the latter, interchangeably with pteroyl glutamic acid) in that order in the p-aminobenzoic acid action; further addition of valine was stimulatory to growth.