THE REACTION OF β,β′-DICHLORODIETHYL SULPHIDE WITH PROTEINS

Abstract

The reaction of β,β′-dichlorodiethyl sulphide with various proteins and their constituents has been tested under relatively mild conditions. Most reactions have been carried out in aqueous media at 25 °C., usually in the presence of sodium chloride. The rate of disappearance of mustard has been followed iodimetrically as an index of the reaction.No reaction could be demonstrated with the prolamins, zein and gliadin, in ethanol. There was a definite reaction with keratin of human skin in which a 24% increment in total sulphur occurred and a more doubtful one with keratein from human hair.The most notable reaction took place with yeast and thymus nucleoproteins in which increases of 250 and 156% in sulphur occurred, respectively. Combination of mustard with both the protein and nucleic acid portions was demonstrated. The extent of these reactions is indicated in terms of milligrams of mustard per gram of substrate as follows: yeast nucleoprotein, 216; thymus nucleoprotein, 47; salmine, 47; globin, 22; yeast nucleic acid, 126. The purines, adenine and guanine, were found to combine readily with mustard at 25 °C., forming thiazans. No reaction could be demonstrated with uracil or thiamine.These experiments have led us to the conclusion that one of the major effects of mustard in its physiological action is the combination and precipitation of the nucleoproteins of the cell, thus inhibiting natural processes of cellular regeneration.