Vitelline-coat lysin: Comparison of lysins among three species in the genus Tegula

Vitelline-coat lysins from two species of marine mollusc of the genus Tegul a, Tegula lischkei and Tegula sp., were purified and their properties compa red with those of Tegula pfeifferi Cross-reaction tests among these three s pecies proved that the lysin action on the vitelline coal was species speci fic. Each of the lysins from these three species is a single, basic polypep tide with a molecular weight of 16 000-17 000 and an isoelectric point of p H 10.5. All of them share a common antibody recognition site(s) for the ant i-T pieifferi lysin antibody. Their amino acid sequences were analyzed usin g intact lysins and peptides separated by reverse phase highperformance liq uid chromatography after V8 proteinase digestion. The amino acid sequences of the N-terminus (Nos 1-66) from the three species showed 98% homology, an d those of the C-terminus (Nos 91-118) showed 89% homology. It was conclude d that the species specificity of the vitelline coat lysin appears to be de termined by a sequence of 24 residues (Nos 67-90) in the middle region of t he molecule.