Functional properties of hemocyanin from Oncomelania hupensis, the intermediate host of Schistosoma japonicum.

The gastropod mollusc, Oncomelania hupensis is a unique intermediate host for the human parasite Schistosoma japonicum. It is a primary factor for the epidemic of schistosomiasis and its distribution is consistent with the epidemic area of schistosomiasis. Here we report the functional properties of hemocyanin of O. hupensis (OhH), a copper-containing respiratory protein which was isolated from its hemolymph and purified by ammonium sulfate fractionation and ultracentrifugation. We identified the protein characters including UV absorption at 340 nm, copper content and quaternary structure. Furthermore, by induction of phenoloxidase and enzyme-linked immunosorbent assay we show that OhH exhibited o-diphenoloxidase activity after limited proteolysis, and shared carbohydrate epitopes with glycoconjugates of S. japonicum.