Critical evaluation of p-nitrophenylphosphorylcholine (p-NPPC) as artificial substrate for the detection of phospholipase C

Phospholipase C (PLC) activity secreted by bacteria as a virulence factor i s commonly detected by use of the artificial substrate p-nitrophenylphospho rylcholine (p-NPPC). We examined several commercially available enzymes (ph osphodiesterases, phosphomonoesterases, phospholipase A, lipase, protease) for their hydrolytic activity towards p-NPPC and compared these results wit h those of PLC tests using phospholipid substrates. Our data indicate that, in addition to PLC, several other enzymes which can affect phosphate eater s are able to hydrolyze p-NPPC. We therefore suggest to use lipid substrate s for correct characterization of bacterial PLCs, especially when whole bac teria or crude enzyme preparations are investigated. (C) 2000 Elsevier Scie nce Inc. All rights reserved.