Phospholipase activity plays no role in the action of colicin K

1. A mutant lacking both detergent-resistant and detergent-sensitive phospholipase A activities is fully sensitive to colicin K. 2. In the absence of cellular phospholipases A, colicin K does not promote hydrolysis of phosphatidylethanolamine. 3. Cells of the colicin-treated mutant lacking lysophosphatidylethanolamine are as abnormally permeable to Co-2+ as the wind type is. 4. Increased levels of lysophosphatidylethanolamine in colicin-treated cells are not necessary for the increased sensitivity to sodium dodecylsulfate.