The Permeability Parameter of the Outer Membrane of Pseudomonas aeruginosa Varies with the Concentration of a Test Substrate, Cephalosporin C HEWINSON, R. GLYN and LANE, DAVID C. and SLACK, MARY P. E. and NICHOLS, WRIGHT W.,, 132, 27-33 (1986), doi = https://doi.org/10.1099/00221287-132-1-27, publicationName = Microbiology Society, issn = 1350-0872, abstract= SUMMARY: The permeability parameter (C) for the movement of cephalosporin C across the outer membrane of Pseudomonas aeruginosa was measured using the widely accepted method of Zimmermann & Rosselet. In one experiment, the value of C varied continuously from 4∙2 to 10∙8 cm3 min−1 (mg dry wt cells)−1 over a range of concentrations of the test substrate, cephalosporin C, from 50 to 5 μm. Dependence of C on the concentration of test substrate was still observed when the effect of a possible electric potential difference across the outer membrane was corrected for. In quantitative studies of β-lactam permeation the dependence of C on the concentration of β-lactam should be taken into account., language=, type=