Über die gebundene Ascorbinsäure tierischer Gewebe

Abstract

Ascorbic acid is present in animal tissues both free and in combination with a protein. Both forms are soluble in H2O. The tissue proteins were precipitated by sulfosalicylic or tri-chloracetic acid, for 10 min. with 0.5 N HC1 in an atmosphere of CO2 at 100[degree]; the bound ascorbic acid was released by hydrolysis of the tissues by HC1, or by pepsin or papain or by autolysis. The bound ascorbic acid is the reserve or depot form of the vit., since it is more stable toward oxidation than the free form; unlike the free form, it is not decreased in guinea pigs on a vit. C free diet. Cell free extracts of tissues contain bound ascorbic acid; so does milk in which it may be set free by heating. Ascorbic acid was detd. by titration with methylene blue.