An overview of proteinase inhibitors

Proteinase inhibitors are proteins in the body that regulate the catalytic activity of proteinases. They are important in a large variety of physiolog ic processes including coagulation digestion, tumor metastasis and immunity . Proteinase inhibitors are categorized as either nonspecific proteinase in hibitors or class-specific proteinase inhibitors. Nonspecific proteinase in hibitors are comprised soley of the alpha macroglobulins, most notably alph a(2)-macroglobulin. Class-specific proteinase inhibitors are subcategorized as serine proteinase inhibitors, aspartic proteinase inhibitors, metallopr oteinase inhibitors, and cysteine proteinase inhibitors. Each subcategory i s made up of numerous inhibitors. As the roles of individual proteinase inh ibitors are determined, the therapeutic use of natural and synthetic protei nase inhibitors is also being investigated. The purpose of this article is to review the history and classification of proteinase inhibitors and their relevance to veterinary medicine.