Interactions of Bacillus subtilis Alkaline Proteinases with α2-Macroglobulin and α1-Antitrypsin

Abstract

Alkaline proteinases of B. subtilis origins bind to α₂-macroglobulin and α₁-antitrypsin of normal human serum with a resulting inhibition of the proteolytic activities. The interaction of subtilopeptidase A with α₂-macroglobulin results in the formation of complexes which, like the complexes formed by trypsin and α₂-macroglobulin, are protective insofar as there is a residual proteinase activity which is resistant to inhibition by α₁-antitrypsin. The observed interactions are potential determinants of host responses to these proteolytic agents.