The Ninhydrin Reaction with Amino-acids and Ammonium Salts.* by Victor

Among the many biological reactions which have attracted attention during recent years, the one bearing the name of Abderhaldenl has been prominent. The simple nature of the underlying idea, that a circulating foreign protein induces in the blood a corresponding and specific defensive ferment which accomplishes its hydrolysis, combined with the obvious importance of its applications, has rendered the reaction the object of numerous investigations. Both theory and results have been assailed from many directions and the reaction is still a matter of doubt, though evidence is steadily accumulating against it.2 The detection of the hydrolysis products of the circulating foreign protein is usually carried out by the dialysis method, and depends ultimately on the detection of these products after dialysis, by the now so called ninhydrin reaction. This latter reaction was discovered by Ruhemann3 who found that a-amino-acids when warmed with triketohydrindene hydrate gave a fine blue color. pand r-amino-acids hardly reacted at all, and Lu-aminoacids when substituted on the amino or carboxyl group, gave a negative reaction. Abderhalden and Schmidt4 confirmed and extended Ruhemann’s observations, and, as far as is known, there is no amino-acid obtained from protein hydrolysis which does not