Purification and Characterization of Membrane-Bound Phospholipase A2 from Rat Platelets1

摘要

Phospholipase A2was solubilized from rat platelet membrane by 1 M KC1 and purified to near homogeneity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and HPLC. The characteristics of the purified membrane-bound enzyme were compared with those of phospholipase A2released from thrombin-stimulated rat platelets (Horigome, K., Hayakawa, M., Inoue, K.,Nojima, S. (1987)J. Biochem. 101, 625–631). The molecular weights, elution profiles on reversed-phase HPLC, and NH2-terminal sequences were identical for the two enzymes. Other characteristics of the two enzymes, such as specific activity, substrate specificity, pH optimum, Ca2+requirement, heat lability, and sensitivity top-bromophenacyl bromide were also indistinguishable. These findings suggest that both enzymes share a common structur