The polysaccharide content and reducing power of proteins and of their digest products

Abstract

The glucosamine content of serum-pseudoglobulin, globoglycoid and seroglycoid are in rough agreement with the generally accepted view that the polysaccharide present in serum proteins is composed of galactose-mannose-glucosamine units. Crystalbumin contains no glucosamine or polysaccharide. Results indicate that ovalbumin contains diman-nose glucosamine (2.6%) and that ovomucoid contains mannose-glucosamine (20%). The reducing power (Hage-dorn-Jensen) of proteins is not dependent upon the polysaccharide content, and tyrosine, tryptophan and cystine probably contribute to the reducing effect. The course of hydrolysis of proteins cannot be followed by reducing power detns. Peptones rich in carbohydrate (containing as much as 35% of polysaccharide) are obtained from serum proteins by peptic digestion followed by acetone precipitation. Conditions affecting enzymic digestion of antitoxin are discussed.