Table II. Phospholipase C activity^a in P.aeruginosa cell fractions.

Strain	Extracellular medium	Outer membrane periplasm	Cytoplasm	Cytoplasmic membrane
PAK	2.80	0.50	0.10	0.68
PAKΔxcpR-Z	0.03	4.74	0.16	0.57
PAK-TC (tatC)	0.01	<0.01	0.04	4.21

^aAssayed by hydrolysis of ρ-nitrophenylphosphorylcholine (NPPC), which is expressed in relative units: ΔOD₄₁₀/min/100 µl × 100. Cultures were adjusted to the same OD₅₉₀ before fractionation. OD₅₉₀ of the original cultures was 1.05 for PAK wild type; 0.99 for PAKΔxcpR-Z; and 1.01 for PAK-TC. Since protein concentration varies between each fraction from the same organism (e.g. supernatant versus cytoplasm), comparisons can only be made between the same fraction (e.g. cytoplasmic membrane or supernatant) of each of the strains.