[Effects of serums and plasmas of various species on a protease of Staphylococcus aureus. Human alpha2-macroglobulin as an inhibitor (author's transl)].

Serums and plasmas from various animals and man inhibited 85-100% of the activity of a purified protease from Staphylococcus aureus, strain M 135 (table 1). The inhibitory effects of corresponding serums and plasmas were approximately equal. The inhibition in human serum was caused by alpha2-macroglobulin. On the other hand, alpha1-antitrypsin proved to be ineffective (table 2). The complex alpha2-macroglobulin-protease could be separated by vertical polyacrylamide discelectrophoresis. Immunelectrophoretic analysis revealed no changes by the staphylococcal protease neither on alpha2-macroglobulin, nor on other human serum proteins. Only fibrinogen was split into at least 2 components (fig. 1).