Pep 5 and
nisin are cationic bactericidal
peptides which were shown to induce
autolysis in Staphylococcus cohnii 22. In contrast to
nisin,
Pep 5 induced lysis could be stimulated in the presence of
glucose. Addition of lipoteichoic
acids (LTA) (D-
alanine:
phosphorus = 0.475:1) inhibited all effects of
Pep 5 on susceptible cells in a molar ratio LTA:
Pep 5 of 10:1. Treatment of S. cohnii 22 with
Pep 5 or
nisin for 20 min and subsequent washing with 2.5 M NaCl released
autolysin activity. Crude preparations of the hydrolyzing
enzymes produced free amino groups as well as
polysaccharide fragments from the
murein backbone, suggesting the presence of a
muramidase or glucosamidase, and
endopeptidase or
amidase. Both
enzyme activities were inhibited by
lipoteichoic acid; they could be fully reactivated by addition of
Pep 5 in sufficient concentrations. The velocity of hydrolysis was not influenced by
nisin, whereas it was doubled in presence of
Pep 5. The results are discussed in view of a possible mechanism of induction of lysis by
Pep 5 and
nisin.