The nature of the binding of penicillin by bacterial cells.

Previous work in this and other laboratories has shown that penicillin is specifically and irreversibly bound by sensitive bacteria (Pasynskii and Katorskaya, 1947; Cooper and Rowley, 1949; Maass and Johnson, 1949a, 1949b; Rowley et al., 1950). It is thought that this binding is closely related to the primary mode of action of penicillin. Attempts have been made to elucidate the nature of this binding. Daniel and Johnson (1953), Cooper (1954a), and Rowley et al. (1950) have studied the effect of various factors on whole-cell uptake of penicillin in an effort to learn something of the chemical nature of the binding. Little has been learned from these studies, however. Studies have been made on cell-free extracts of untreated cells with a view toward characterizing the penicillin-binding component (Daniel and Johnson, 1953; Cooper, 1954b; Eagle, 1954). The recent discovery by Cooper (1955) that the penicillin-binding component is highly unstable indicates that isolation of this component from untreated cells will involve serious difficulties. In this work an attempt was made to isolate and identify the penicillin-cell complex from cells treated with 5s" penicillin. By this approach it was hoped to discover both the identity of the binding component and the site or sites on the penicillin molecule which may be involved in the binding.