The Association of the Penicillin-binding Component of Staphylococcus aureus with a Lipid Fraction

Abstract

SUMMARY: Radiopenicillin is strongly bound by ultra-microscopic lipid-containing particles liberated on mechanical rupture of Staphylococcus aureus cells. The binding resembles that of intact cells in that it is irreversible and only occurs to a limited extent, but differs in that 7-12 times as much penicillin is bound per unit dry weight of material. The supernatant after centrifuging down the lipid particles decreases the titre of added penicillin as indicated by diffusion assay, possibly by a small irreversible inactivation superimposed upon a ‘reversible’ type of binding.