Characterization of extracellular phospholipase A2 in rheumatoid synovial fluid.
Phospholipase A2 (PLA2) activity has now been identified in rheumatoid synovial fluids. This PLA2 is a calcium-requiring protein of MW 11,000 with a neutral pH optimum. Its activity was inhibited by high concentrations of Mg2+, and by the active site-directed histidine reagent p-bromophenacyl bromide. Ionic and nonionic detergents, or the sulfhydryl reagent dithiothreitol caused loss of enzyme activity. Synovial fluid PLA2 did not interact with sulphated mucopolysaccharides such as heparin or chondroitin sulphate. Release and sequestration of PLA2 in the joint space may contribute to the characteristic rheumatoid inflammatory changes.
D000098:Acetophenones / Q000494:pharmacology; D001172:Arthritis, Rheumatoid / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000494:pharmacology; D003840:Deoxycholic Acid / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism; D008970:Molecular Weight; D017830:Octoxynol; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D011092:Polyethylene Glycols / Q000494:pharmacology; D013582:Synovial Fluid / Q000201:enzymology*
D000098:Acetophenones; D003840:Deoxycholic Acid; D011092:Polyethylene Glycols; D017830:Octoxynol; D006493:Heparin; D002809:Chondroitin Sulfates; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D008274:Magnesium; C006821:4-bromophenacyl bromide; D002118:Calcium; D004229:Dithiothreitol