Abstract
Crystalline Q-enzyme was prepared from potatoes by ethanol fractionation followed by crystallization from ammonium sulfate. The course of the preparation was followed electrophoretically. The effects of temp. and ions on the enzyme were studied. The enzyme is unstable in soln. at 30[degree] in the absence of substrate and is activated by ammonium sulfate. White-skinned potatoes and red-skinned potatoes after winter storage gave very low yields of enzyme.