Glycine

GLYCINE (from Greek glycos-sweet and kolla-glue) (syn. glycine), alpha-aminoacetic acid, CH₂.NH₂.COOH, one of the principal amino acids of protein; especially large amounts of G. are found in glue and silk. Crystals with a sweet taste, easily soluble in water, insoluble in alcohol and ether; melting point 232°. In the organism, glycine occurs in the free state in the blood and sometimes in the urine; in the form of paired compounds—in the composition of glycocholic acid (in bile) and hippuric acid (in the urine of herbivores). G., unlike most other amino acids, can be synthesized in the animal organism (from acetic acid and NH₃). G. participates in the organism in the neutralization of certain poisonous metabolic products; and of medicinal substances of an acidic nature, forming with them non-toxic paired compounds. In laboratory practice, G. is sometimes used in the preparation of buffer solutions: a decimolar solution of G., mixed in various proportions with decinormal caustic soda, gives buffer mixtures for pH from 8.2 to 10.1.