A spider (Araneus ventricosus) chymotrypsin inhibitor that acts as an elastase inhibitor and a microbial serine protease inhibitor.

Spider-derived Kunitz-type serine protease inhibitors have been shown to exhibit plasmin and elastase inhibition activity and potassium channel blocking activity, but thus far, no additional roles for spider-derived chymotrypsin inhibitors have been elucidated. In this study, a spider (Araneus ventricosus) chymotrypsin inhibitor (AvCI) that acts as an elastase inhibitor and a microbial serine protease inhibitor was identified. AvCI is a 70-amino acid mature peptide that displays eight conserved cysteine residues and a P1 lysine residue. Recombinant AvCI expressed in baculovirus-infected insect cells demonstrated inhibitory activity against chymotrypsin (Ki 49.85 nM), but not trypsin, which defines a role for AvCI as a spider-derived chymotrypsin inhibitor. AvCI also exhibited inhibitory activity against microbial serine proteases such as subtilisin A (Ki 20.51 nM) and proteinase K (Ki 65.42 nM). Furthermore, AvCI exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or plasmin; however, AvCI strongly inhibited human neutrophil elastase (Ki 8.74 nM) and porcine pancreatic elastase (Ki 11.32 nM), indicating that AvCI acts as an anti-elastolytic factor. These findings constitute molecular evidence that AvCI acts as an inhibitor against chymotrypsin, microbial serine proteases, and elastases. This paper provides a novel view of the functions of a spider-derived chymotrypsin inhibitor. Copyright © 2013 Elsevier Inc. All rights reserved.

Citation

Hu Wan, Kwang Sik Lee, Bo Yeon Kim, Miao Yuan, Sha Zhan, Hong You, Jianhong Li, Byung Rae Jin. A spider (Araneus ventricosus) chymotrypsin inhibitor that acts as an elastase inhibitor and a microbial serine protease inhibitor. Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology. 2013 May;165(1):36-41

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PMID: 23499942

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