ISOLATION AND STRUCTURAL DETERMINATION OF SEMINAL VESICLE-SPECIFIC PEPTIDES OF THE TERRESTRIAL ISOPOD, ARMADILLIDIUM-VULGARE

During the course of purifying the androgenic gland hormone of the ter restrial isopod, Armadillidium vulgare, that induces post-embryonic se x differentiation, four structurally related peptides, were obtained a nd their structures determined by a combination of microsequence and m ass spectral analg;ses. These peptides were found to exist speciffical ly in the seminal vesicle and vas deferens by a Western blot analysis, therefore being designated as seminal vesicle-specific peptides (SVSP s). They had essentially the same amino acid sequences but differed fr om one another in the truncation of several residues at the N-terminus and of one residue at the C-terminus, and in the modification of glut amine to pyroglutamate at the N-terminus. The longest peptides, SVSP-4 , consisted of 60 amino acid residues with two intramolecular disulfid e bridges. There is no significant homology with any other vertebrate or invertebrate peptides.