SUMMARY: Radiopenicillin is strongly bound by ultra-microscopic lipid-containing particles liberated on mechanical rupture of 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.

There is a correlation between the distribution of () the penicillin-binding component (p.b.c.), () S from radiopenicillin pretreated cells, and () lipid phosphorus, in the three fractions produced on rupture either in distilled water or in a formaldehyde solution. Rupture in formalin appears to allow the cells walls to retain most of the lipid particles and p.b.c. but only a little extra of the dry weight of the cells. Thus penicillin reacts with a lipid-containing fraction close to the cell wall in intact organisms. At least as much more p.b.c. is liberated on rupture of the cells as was available to the penicillin in the intact cell, but p.b.c. is somewhat unstable after rupture. These data are discussed in the light of evidence in the literature that penicillin may react initially with the osmotic barrier of bacteria.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error