The use of alpha 2-antiplasmin as a model for the demonstration of complex reversibility in serpins.
Human alpha 2-antiplasmin readily forms 1:1 complexes with either trypsin or chymotrypsin at independent but overlapping reactive sites. In the absence of alpha 2-macroglobulin, complex dissociation and enzyme release can be demonstrated without regeneration of inhibitory activity. However, in the presence of this inhibitor the dissociation of alpha 2-antiplasmin-chymotrypsin complexes or alpha 2-antiplasmin-trypsin complexs yields functionally active inhibitors which can now inactivate trypsin and chymotrypsin, respectively. These results clearly indicate that Serpin-proteinase complexes can dissociate to give both active inhibitor and enzyme. If the enzyme is trapped by alpha 2-macroglobulin, in vivo, it is possible that the inhibitor may be recycled for further use.
Shieh
B H
BH
Department of Biochemistry, University of Georgia, Athens 30602.
Potempa
J
J
Travis
J
J
D002918:Chymotrypsin / Q000378:metabolism*; D007700:Kinetics; D011480:Protease Inhibitors / Q000378:metabolism*; D011485:Protein Binding; D014357:Trypsin / Q000378:metabolism*; D000979:alpha-2-Antiplasmin / Q000378:metabolism*
D011480:Protease Inhibitors; D000979:alpha-2-Antiplasmin; D002918:Chymotrypsin; D014357:Trypsin