title: Phospholipase C (heat-labile hemolysin) of Pseudomonas aeruginosa: purification and preliminary characterization.
abstract: Phospholipase C (heat-labile hemolysin) was purified from Pseudomonas aeruginosa culture supernatants to near homogeneity by ammonium sulfate precipitation followed by a novel application of DEAE-Sephacel chromatography. Enzymatic activity remained associated with DEAE-Sephacel even in the presence of 1 M NaCl, but was eluted with a linear gradient of 0 to 5% tetradecyltrimethylammonium bromide. Elution from DEAE-Sephacel was also obtained with 2% lysophosphatidylcholine, and to a lesser extent with 2% phosphorylcholine, but not at all with choline. The enzyme was highly active toward phospholipids possessing substituted ammonium groups (e.g., phosphatidycholine, lysophosphatidylcholine, and sphingomyelin); however, it had little if any activity toward phospholipids lacking substituted ammonium groups (e.g., phosphatidylethanolamine, phosphatidylserine, and phosphaditylglycerol). Collectively, these data suggest that phospholipase C from P. aeruginosa exhibits high affinity for substituted ammonium groups, but requires an additional hydrophobic moiety for optimum binding. The specific activity of the purified enzyme preparation increased 1,900-fold compared with that of culture supernatants. The molecular weight of the phospholipase C was estimated to be 78,000 by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Sephacryl S-200 column chromatography and was 76,000 by high-performance size exclusion chromatography. The isoelectric point was 5.5. Amino acid analysis showed that phospholipase C was rich in glycine, serine, threonine, aspartyl, glutamyl, and aromatic amino acids, but was cystine free.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid; D003902:Detergents / Q000494:pharmacology; D006358:Hot Temperature; D007526:Isoelectric Point; D010740:Phospholipases / Q000302:isolation & purification*; D010743:Phospholipids / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D003902:Detergents; D010743:Phospholipids; D010740:Phospholipases; D010738:Type C Phospholipases