Synthetic peptide from lipocortin I has no phospholipase A2 inhibitory activity

Abstract

Two anti-inflammatory peptides corresponding to a high amino acid similarity region between lipocortins were synthesized and tested on their ability to inhibit porcine pancreatic phospholipase A₂. Kinetic assays using monomeric and aggregated phospholipids did not reveal any phospholipase A₂ inhibitory activity. The peptides did not inhibit phospholipase A₂ activity on monolayers of negatively charged substrate and did not prevent phospholipase A₂ action on mixed micelles of 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphocholine and sodiumdeoxycholate. Ultraviolet difference spectroscopy did not show binding of the peptides to phospholipase A₂. Therefore we conclude that these anti-inflammatory peptides do not inhibit pancreatic phospholipase A₂ in vitro, in contrast to the results recently published [(1988) Nature 335,726–730].