Article: PDF OnlyHuman Disc Phospholipase A2 is InflammatoryFranson, Richard C. MS, PhD*; Saal, Joel S. MD†; Saal, Jeffrey A. MD†Author Information From *Virginia Commonwealth University, Department of Biochemistry and Molecular Biophysics, Richmond, Virginia, and the †San Francisco Spine Institute, Daly City, California. Spine: June 1992 - Volume 17 - Issue 6 - p S129-S132 Free Abstract Human discs have been demonstrated to contain high levels of phospholipase A2. As the enzyme responsible for the liberation of arachidonic acid from membranes, this enzyme has a theoretical inflammatory potential. Hernlated lumbar discs have a higher level of phospholipase A2 than do normal discs. The purpose of this study was to evaluate the inflammatory capability of purified human disc phospholipase A2. Phospholipase A2 extracted and purified from human disc was found to be inflammatory. Its inflammatory capability was directly related to its ability to function enzymatically. When the enzyme was treated with parabromophenacyl bromide (p-BPB) to specifically alkylate the active site histidine and block catalytic activity, the ability of the modified protein to produce edema was markedly reduced. Careful regulation of the activity of this enzyme is important in vivo because its inflammatory potential could result in disc degeneration and nerve injury. © Lippincott-Raven Publishers.