Abstract
Hornet silk (HS) collected from hornet nests can be processed easily into a regenerated film through dissolution into a concentrated salt solution, followed by desalting and drying. In fact, HS requires no pre-dissolution refining. Moreover, dissolution processes can be performed at room temperature. Although the risk of protein degradation caused by heating during processing is low, the actual degradation effects remain unclear. Results of detailed SDS-PAGE analyses of cocoons and regenerated films conducted for this study confirmed that part of Vxsilk4 (x = s, a), a major protein constituting HS, was degraded in regenerated films prepared from cocoons of Vespa simillima and Vespa analis. The addition of PMSF, a specific inhibitor of serine proteases, inhibited this degradation, suggesting that enzymes present in the nest or cocoon acted during film fabrication. By contrast, no similar protein degradation was observed in a film prepared from a Vespa mandarina cocoon.
