Mil'lon's reac'tion

A color reaction given by all proteins which contain tyros in. It consists of a pink or red color upon mixture treating of mercuric with Millon's reagent, nitrite and nitrate.a The reaction is due to the presence of tyros in in the protein molecule and especially to the free hydroxyl group. When the hydrogen of the hydroxyl group has been substituted by some other group, the M. r. is negative. M's test (for salicylic acid, phenol, or tyros in). A solution of mercury in nitric acid; used to show aromatic compounds which contain one hydroxyl group united with a benzene or naphthalene nucleus with which no nitrogen group is connected. Such compounds are colored red by 1 or 2 drops of the reagent to a c.c. of the solution containing the compound.