Nitrogenous Constituents of the Potato

Abstract

OSBORNE and Campbell¹ isolated a globulin from the expressed sap of minced potatoes. By extracting the crushed potato residue with 10 per cent sodium chloride, they were able to obtain an additional amount of protein which they considered was identical with the globulin contained in the press juice. When a solution of this protein in 10 per cent sodium chloride was gradually heated, a flocculent coagulum was formed at about 60° C., and further precipitates were obtained at higher temperatures up to 80° C. At this temperature coagulation of all the protein was complete, although a minute amount of proteose material appeared to remain in solution. The authors concluded that the only true protein present in potato was a globulin, with rather indeterm-