| Type: | Family | Name: | Proteinase inhibitor I1, Kazal metazoa |
| Description: | This family of Kazal eukaryotic proteinase inhibitors, belongs to MEROPS inhibitor family I1, clan IA. They inhibit serine peptidases of the S1 family () []. They are restricted to the metazoa (arthropoda and chordata), and includes a single exception in the alveolata (apicomplexa). No members are found in nematodes, fungi or plants.Kazal inhibitors, which inhibit a number of serine proteinases (such as trypsin and elastase), belong to family of proteins that includespancreatic secretory trypsin inhibitor; avian ovomucoid; acrosin inhibitor; and elastase inhibitor. These proteins contain between 1 and 7 Kazal-typeinhibitor repeats [, ].The structure of the Kazal repeat includes a large quantity of extended chain, 2 short alpha-helices and a 3-stranded anti-parallel beta sheet [].The inhibitor makes 11 contacts with its enzyme substrate: unusually, 8 of these important residues are hypervariable []. Altering the enzyme-contact residues, and especially that of the active site bond, affects the the strength of inhibition and specificity of the inhibitor for particular serine proteinases [, ]. | Short Name: | Prot_inh_Kazal-m |
