Some chemical and biological characteristics of showdomycin.

The chemical properties of showdomycin, a maleimide type antibiotic, were very similar to, but its biological properties rather different from, those of N-ethylmaleimide. Another maleimide derivative, citraconimide, showed very low reactivity both in chemical and biological reactions compared with the above two compounds. The results of quantitative analyses of cellular sulfhydryl content of Escherichia coli did not indicate a perfect correspondence between the elimination of cellular sulfhydryl and the inhibition of cell growth by these maleimide type compounds.