Abstract
An accurate insight into the intermediary metabolism of carbohydrates is dependent in part upon a knowledge of the structure of glycogen and blood sugar. Water has been and still is the most frequently used medium for the study of the chemical properties of the carbohydrates, particularly of the sugars. It occurred to us that liquid ammonia might also be a solvent for the sugars and a medium for the study of the chemical properties of the polysaccharides. Schmid and his collaborators 1 , 2 , 3 , 4 have studied some of the physical properties of the polysaccharides in liquid ammonia and have prepared a few of the alkali metal salts of them.
The monosaccharides, arabinose, glucose, levulose, and galactose; the disaccharides, sucrose, maltose and lactose; and the hexoside, α-methylglucoside, are readily soluble in liquid ammonia at—33.5°C. and at 25°C. Glucose is soluble to the extent of 40 gm. per cc. Maltose is the least soluble of the sugars mentioned. α-methylglucoside is soluble to the extent of 36 gm. per 100 cc. Glycogen is dispersed in liquid ammonia to give an opalescent solution. Liquid ammonia solutions of sugars that have been thoroughly dried from water and placed in sealed glass tubes show no caramelization even after standing for a year in the diffuse light of the laboratory. However, caramelization takes place readily when a small quantity of moisture is present. When the ammonia is allowed to evaporate from these solutions, the monosaccharides remain as very thick syrups, which dry in a vacuum desiccator over sulphuric acid to hard glassy substances.
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