Staphylococcal penicillinase. I. Inhibition and stimulation of activity.

Abstract Saz, Arthur K. (National Institute of Allergy and Infectious Diseases, Bethesda, Md.), Dolores L. Lowery, and Leah J. Jackson. Staphylococcal penicillinase. I. Inhibition and stimulation of activity. J. Bacteriol. 82:298–304. 1961.—The penicillinase extracted from a penicillin-resistant strain of Staphylococcus aureus was shown to be inhibited up to 70% by various dipeptides and particularly by d-valyl-d-valine. It is of interest that the nucleus of penicillin contains d-valine. Various dipeptides formed by condensing amino acids and metal-binding compounds such as benzidine and biphenyl have been shown to inhibit penicillinase activity in considerably lower concentration than the dipeptides composed of amino acids alone. Contrariwise, it has been found that various alcohols, and particularly n-propanol, markedly stimulate the activity of the penicillinase both in whole cells and in cell-free extracts. The alcohols fall into a symmetrical series in respect to stimulatory activity with methyl n-butanol > amyl > isoamyl > octyl. Evidence is also presented showing that staphylococcal penicillinase is associated with the particulate fraction of the cell and it is postulated that the alcohols stimulate as a result of bringing insoluble enzyme and substrate into closer apposition. Bacillus subtilis strain 749 penicillinase, which is essentially soluble, is not stimulated by the alcohols. The possibility is presented based on fractionation of crude enzyme on a diethylamino-ethyl cellulose column that different species of penicillinase exist in S. aureus.