Inhibitory activity of cardiotoxin II of the Indian cobra and certain antibiotics on lysis of bacteria promoted by lysozyme

Abstract

Cardiotoxin II exerts a powerful, but incomplete and irreversible, inhibitory action on the lysis of killed cells of Micrococcus lysodeikticus by egg-white lysozyme (N-acetylmuramide glucanohydrolase, EC 3.2.1.17). The antibiotics thiostrepton, a macrocyclic lactone, as well as the antibacterially inactive corresponding open chain compound and polymyxin B are found to act in the same manner. But antibiotics such as gramicidin Dubos, gramicidin S. etamycin, the antibacterially active triformyl derivative of polymyxin and the nearly inactive tetraformyl derivative of polymyxin B do not demonstrate any inhibitory action on lysozyme-induced lysis.