사람 양수중 다종의 세포외성 포스포리파제 A2의 부분정제 및 특성

Partial Purification and Characterization of Multiple Forms of Extracellular Phospholipase A2 in Human Amniotic Fluid

Multiple forms of extracellular phospholipase A2 have been detected in human amniotic fluid (HAF). When HAF was subjected to heparin-Sepharose column chromatography, phospholipase A2 activity was detected in both heparin-non binding and binding fraction. The activity of heparin-non binding fraction was further purified by sequential uses of column chromatographies on butyl-Toy-opearl 650M and DEAE-Sephacel. DEAE-Sephacel fraction contained three different phospholipase A2 activities (Peak I, II, III). The molecular weight of DEAE-Sephacel fraction phospholipase A2 determined by SDS-PAGE were about 52KDa (Peak I). Peak II, III required micromolar Ca2+ ion for its maximum activity, but Peak I enzyme showed calcium independent phospholipase A2 activity and showed broad range of pH (6.0~10.0) optimum. All these enzymes were not recognized by a monoclonal antibody raised against phospholipase A2 from human synovial fluid. These results suggest that HAF might contain multiple forms of extracellular phospholipase A2, which may neither belong to the 14KDa group II phospholipase A2 family nor cytosolic phospholipase A2.