The present invention relates to recombinant proteins having serine protease polypeptides that have serine protease activity in the presence of a serine protease inhibitor and that are able to completely or partially reverse a serine protease inhibitor effect, for example in a subject treated with a serine protease inhibitor. More specifically, described herein are recombinant proteins and methods for completely or partially reversing an anti-coagulant effect of a coagulation inhibitor.