The Zincin Enzyme Family

The zincin proteases remodel the stroma during development and around tissues that have been injured or stressed (Sects. 13.2.4). All proteases possess one of the three types of activities (a) (Sects. 13.2.5) that cut within a polypeptide (b) (Sects. 13.3.1) that cut at the C- orN-terminus and (c) peptidases that cut small polypeptides. The five structural classes of proteases are listed in Table 8.1 and the enzymatic activities of the various metallopro-tease classes and subclasses are listed in Table 8.2. 

All human metalloendoproteinases are metzincins, named for a downstream methionine residue involved in regulating catalysis by mediating a critical turn that brings an adjacent tyrosine or proline residue close to the catalytic zinc ion. Matrilysins (also called matrix metalloendoproteinases, MMPs) are the major class of metzincin endopeptidases involved in collagen and stromal degradation. The other two classes, adantalysins and 

Catalytic site Genes Representative0 Catalytic mechanism 

Serine 175 Tryp sin/chymo tryp sin/ caspasesd Residue forms OH from bound H20 

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