Title: Antithrombin, the Prototypic Heparin-Binding Protein
Abstract: This chapter highlights the importance of antithrombin which is a member of the serpin superfamily of proteins that includes more than 40 proteins. Each serine protease inhibitor usually plays an important role in inhibiting excessive action of its specific target protease. Such serpins combine with proteases to form inactive complexes, which are then cleared from circulation. Serpins are the "suicide substrates" for their target proteases which interact with the active sites on the proteases and are cleaved. The cleaved serpins remain in inactive complexes with their proteases. These complexes are apparently stable acyl enzyme intermediates. The heparin causes a conformation change in the serpin which facilitates the protease/serpin binding and at the same time, exposes the active center of the serpin to the protease. For antithrombin, the target proteases are thrombin, factor Xa, and perhaps factors XIa, IXa, and XIIa. Since the role of a serpin is to prevent the harmful action of its target protease, it must inactivate the protease rapidly enough under physiological conditions to fulfill this function.
Publication Year: 1998
Publication Date: 1998-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
Access and Citation
Cited By Count: 5
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