Purification and molecular cloning of SE-cephalotoxin, a novel proteinaceous toxin from the posterior salivary gland of cuttlefish Sepia esculenta

摘要: Abstract Cephalopods contain toxins in their salivary glands, presumably to paralyze prey animals such as crabs and bivalves. Proteinaceous (called cephalotoxins) with crab lethality have previously been purified from three species of octopodiform cephalopods (octopuses) but detailed properties primary structures remained unknown. In this study, glands six decapodiform were newly found be toxic; cuttlefish lethal only squid both mice crabs. A proteinaceous toxin (named SE-cephalotoxin) the gland Sepia esculenta was soluble high-salt solvents. This unique solubility enabled us purify SE-cephalotoxin by gel filtration HPLC hydroxyapatite HPLC. shown a 100 kDa monomeric glycoprotein an LD 50 (against crabs) 2 μg/kg. Based on determined partial amino acid sequence, full-length cDNA (3402 bp) coding for cloned RT-PCR RACE. The precursor protein (1052 residues) is composed signal peptide (region 1–21), propeptide 22–29) mature 30–1052). database search failed find any proteins sharing homology SE-cephalotoxin.