Purification of anti-HIV protein from purple fluid of the sea hare Bursatella leachii de Blainville

The purple fluid of Bursatella leachii, already found to have anti-HIV activity, was selected and tested for purification and characterization of an anti-HIV protein. Only one fraction showed anti-HIV activity at the minimum inhibition concentration of 50 mug/ml. This purified anti-HIV protein has been named as Bursatellanin-P after the animal species Bursatella leachii. About 3 mg of the pure protein was obtained from 1000 ml of purple fluid. The anti-HIV activity increased by about 135-fold in the purified sample, as compared with the crude purple fluid. The purified protein, which showed anti-HIV activity, was a single unit with a molecular weight of 60 kDa. The protein was stable between pH 5.8 and 8.0. It lost its activity with heating at 60degreesC for 10 minutes and also with extreme pH values of 2.0 or 10. The protein was resistant to digestion of proteinase K and mercaptoethanol.