A four-Kazal domain protein in Litopenaeus vannamei hemocytes.

A cDNA clone coding for a Kazal protein was isolated from a cDNA library of Litopenaeus vannamei hemocytes. The full-length cDNA sequence is 1.32 kb long and encodes a 24 kDa protein. Four Kazal domains, 43-46 residues long, were detected in the deduced primary structure. Apparently, the first and second domains do not have inhibitory activity, as predicted by the sequence between the second and third Cys. The third and fourth domains have the sequences CPEIYAPVC and CPKNYRPVC, indicating that they are able to inhibit subtilisin- and trypsin-like proteins, respectively. mRNA Levels of the shrimp Kazal protein were modified after injection of Vibrio alginolyticus, suggesting a probable role in the immune response.