Mytilus edulis hemolymph contain prodynorphin.

We have characterized a prodynorphin (prodyn) molecule in hemocytes and hemolymph of the bivalve mollusk Mytilus edulis. The ca. 16-kDa protein was purified by cut-off filtration prepurification, anti-leucine-enkephalin affinity column separation followed by reversed-phase HPLC. Its primary sequence was determined by Edman degradation, endoproteinase Glu-C digestion and CNBr treatment. Mytilus prodyn contains, alpha-neo-endorphin, dynorphin-A and dynorphin-B at the C-terminus, exhibiting 100, 70.5 and 85% of identity with the rat prodyn-derived counterparts, respectively. The number of leucine-enkephalins in this precursor is identical to that found in vertebrates. Mytilus prodyn is distinguished from that found in leeches in that the N-terminus is longer. Additionally, by sequence comparison, the presence of an orphanin FQ-like peptide, exhibiting 50% sequence similarity with that found in mammals, is demonstrated. This report constitutes the first complete biochemical characterization of a prodyn in a non-parasitic invertebrate and mollusk.