Extracellular phospholipase A2 and lysophospholipase produced by Vibrio vulnificus

Abstract

Phospholipase A2 and lysophospholipase activities were detected in the culture supernatant fluids of a virulent strain of Vibrio vulnificus. The phospholipase A2 was inactivated by heating at 56 degrees C for 30 min, had an apparent molecular weight of greater than or equal to 80,000 (estimated by gel filtration with Sephadex G-75), and a pI of ca. 5.0. Phospholipid hydrolysis was unaffected by Ca2+ or ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid and was optimal at pH 5.0 to 5.5. The lysophospholipase was not affected by heating at 56 degrees C for 30 min but was inactivated at 100 degrees C and had an apparent molecular weight of greater than or equal to 80,000 and a pI of ca. 4.0. The enzymes were detected coincidentally with a previously described extracellular cytolysin of V. vulnificus; however, they were physically separable from the toxin (which did not possess phospholipase A, C, or D activity) by gel filtration with Sephadex G-75.