Purification and characterization of a cytolytic protein from purple fluid of the sea hare, Dolabella auricularia.

A novel cytolytic factor, dolabellanin P, was purified to apparent homogeneity from the purple fluid of the sea hare, Dolabella auricularia. Purified dolabellanin P is a single polypeptide of 60 kDa. The amino acid composition and the N-terminus of the factor were also determined. This factor nonspecifically lysed all the cells tested at 50-200 ng protein/ml. Dolabellanin P caused complete cytolysis within 2 h. The factor is distinct from antineoplastic glycoproteins previously isolated from eggs (aplysianin E) or albumen gland (aplysianin A) of Aplysia kurodai in terms of certain cytolytic properties. These results suggest that dolabellanin P, found in the sea hare, a marine invertebrate, is a new cytolytic factor.