Structures Responsible for the Characteristic Purple Color Development in Diphenylamine Reaction with Serum.

Abstract

It has been shown that deoxyhexoses and hexals react with the Dische diphenylamine reagent in a characteristic manner. No other structures except sialic acid and related compounds have been found to react in the same fashion. A deoxyhexose structure for sialic acid has been proposed by Gottschalk. The color given by sialic acid when heated with the reagent is therefore accounted for by the presence of the deoxyhexose. Since sialic acid is considered to be a common constituent of the glycoproteins (mucoproterns), the color given by these substances and serum when heated with the Dische reagent appears to be due to the deoxyhexose present in sialic acid.