Pii: S0041-0101(00)00237-3

We have isolated and characterized a novel hemolytic protein from the venom of the Hawaiian box jelly®sh (Carybdea alata). Hemolysis of sheep red blood cells was used to quantitate hemolytic potency of crude venom extracted from isolated nematocysts and venom after fractionation and puri®cation procedures. Hemolytic activity of crude venom was reduced or lost after exposure to the proteolytic enzymes trypsin, collagenase and papain. The activity exhibited lectin-like properties in that hemolysis was inhibited by d-lactulose and certain other sugars. Activity was irreversibly lost after dialysis of crude venom against divalent-free, 20 mM EDTA buffer; it was optimal in the presence of 10 mM Ca or Mg. Two chromatographic puri®cation methods, size fractionation on Sephadex G-200 and anion exchange with quaternary ammonium, provided fractions in which hemolytic activity corresponded to the presence of a protein band with an apparent molecular weight of 42 kDa by SDS±PAGE. We have designated this protein as CAH1. The N-terminal sequence of CAH1 was determined to be: XAADAXSTDIDD/GIIG. q 2001 Elsevier Science Ltd. All rights reserved.