Untersuchungen über die proteolytische Wirkung des Saftes der Kartoffelknolle. II. Mitteilung

Abstract

Protein preparations with different proteinase activities have been obtained from potato tuber sap by repeated fractional saturation with ammonium sulphate. The enzyme can be strongly enriched by half-saturation. Comparative determination of the activity with different substrates showed that the same enzyme is active in all the preparations. The differences in composition of the preparations, deduced from the solubilities and enzyme activities, have been confirmed by means of paper electrophoresis. Six protein zones were demonstrated by staining with Amido Black 10 B. None of the zones was identical with the enzyme whose speed of migration was determined by cleavage of casein.