Purification of a Soluble Phospholipase A2 from Synovial Fluid in Rheumatoid Arthritis1

Abstract

A soluble phospholipase A₂ (PLA₂) was purified 4,500-fold from human rheumatoid synovial fluid. Preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis yielded two bands of PLA₂ activity of molecular weights 15,000 and 17,000 and pI 4.2–5.0. Purified PLA₂ had absolute 2-acyl specificity, and hydrolyzed phosphatidylcholine with optimal activity at pH 7.5–8.0 and phosphatidylethanolamine with optimal activity at pH 7.0. Human synovial fluid PLA₂ did not crossreact with anti-human pancreatic PLA₂, as tested by radioimmunoassay.