Proteolysis and deglycosylation of human C1̄ inhibitor. Effect on functional properties

Abstract

The effects of proteolysis and deglycosylation on C1̄ inhibitor (C1̄Inh) were tested with respect to both its ability to form complexes with C1̄s and its capacity to block C1 autoactivation. Limited proteolysis of C1̄Inh by Staphylococcus aureus V8 proteinase, proline-specific endopeptidase or elastase generated a major high-M(r) (~ 86000) fragment. In contrast with the fragment produced by elastase, which was inactive, the fragments resulting from V8 proteinase and proline-specific endopeptidase treatment retained activity. Deglycosylation with N-glycanase or O-glycanase, or both, had no major effect on the functional activity of C1̄Inh.