ASPARAGINE, a naturally occurring base found in plants belonging to the families Leguminosae and Cruciferae, and notice ably in asparagus. It has the structure and belongs to the important group of amino-acids, being both an acid, by virtue of the carboxyl group, and a base, by virtue of the two amino (NH2) groups. Owing to the presence of an "asymmetric carbonation" (C above), it should exist in two optically active forms and one inactive form (see STEREO-CHEM ISTRY).
A. Piutti (188 7) synthesized the asparagines from the mono methyl ester of inactive aspartic acid by heating it with alcoholic ammonia. In this way both asparagines were obtained and were separated by picking out the hemihedral crystals. Laevo aspara gine, which was isolated by L. N. Vauquelin in 1805, is slightly soluble in cold water and readily soluble in hot water and crystal lizes in prisms, containing one molecule of water of crystallization, the anhydrous form melting at 234-235° C. Nitrous acid converts it into malic acid, HOOC.CHOH.CH2.COOH. It is laevo-rotatory in aqueous or in alkaline solution, and dextro-rotatory in acid solution (L. Pasteur, 1851) . Dextro-asparagine was first found in 1886 in the shoots of the vetch (Piutti). It forms rhombic crystals possessing a sweet taste. It is dextro-rotatory in aqueous or alkaline solution, and laevo-rotatory in acid solution.
Hydrolysis by means of acids or alkalis converts the asparagines into aspartic acid ; whilst on heating with water in a sealed tube they are converted into ammonium aspartate.