A four-domain Kunitz-type proteinase inhibitor from Solen grandis is implicated in immune response

► We identified a Kunitz-type proteinase inhibitor gene from Solen grandis. ► SgKunitz exhibited a broad expression patterns in tissues. ► SgKunitz could be induced significantly by PAMPs stimulation. ► Recombinant SgKunitz could inhibit the activity of trypsin and chymotrypsin.