Abstract
The growth inhibiting activity of the antibiotic showdomycin, a nucleoside derivative of maleimide, on E. coli Umezawa was specifically reversed by ribo- and deoxyribo-nucleosides and thiol compounds such as L-cysteine, glutathione and β-mercaptoethanol. No effect on the reversal of the anti bacterial activity of showdomycin was observed for purine, pyrimidine bases, nucleoside phosphates, ribose, deoxyribose and phosphate derivatives of ribose. Of the 19 amino acids tested, L-cysteine was the only one which is able to reverse the activity of showdomycin. All other amino acids were ineffective.
