title: Phospholipid composition and phospholipase A activity of Neisseria gonorrhoeae.
abstract: Exponential-phase cells of Neisseria gonorrhaeae 2686 were examined for phospholipid composition and for membrane-associated phospholipase A activity. When cells were harvested by centrifugation, washed, and lyophilized before extraction, approximately 74% of the total phospholipid was phosphatidylethanolamine, 18% was phosphatidylglycerol, 2% was cardiolipin, and 10% was lysophosphatidylethanolamine. However, when cells still suspended in growth medium were extracted, the amount of lysophosphatidylethanolamine decreased to approximately 1% of the phospholipid composition. This suggests that a gonococcal phospholipase A may be activated by conditions encountered during centrifugation and/or lyophilization of cells preceding extraction. Phospholipase A activity associated with cell membranes was assayed by measuring the conversion of tritiated phosphatidylethanolamine to lysophosphatidylethanolamine. Optimal activity was demonstrated in 10% methanol at pH 8.0 to 8.5, in the presence of calcium ions. The activity was both detergent sensitive and thermolabile. Comparisons of gonococcal colony types 1 and 4 showed no significant differences between the two types with respect to either phospholipid content or phospholipase A activity.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002308:Cardiolipins / Q000032:analysis; D002462:Cell Membrane / Q000201:enzymology; D002474:Cell-Free System; D009344:Neisseria gonorrhoeae / Q000032:analysis* / Q000201:enzymology; D010714:Phosphatidylethanolamines / Q000032:analysis; D010715:Phosphatidylglycerols / Q000032:analysis; D010740:Phospholipases / Q000378:metabolism*; D010743:Phospholipids / Q000032:analysis* / Q000378:metabolism
chemical_list: D002308:Cardiolipins; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D010743:Phospholipids; D010740:Phospholipases; D002118:Calcium