Protein and cell membrane iodinations with a sparingly soluble chloroamide, 1,3,4,6-tetrachloro-3a,6a-diphrenylglycoluril.

Abstract Films of 1,3,4,6-tetrachloro-3a,6a-diphenylglycoluril (conveniently “plated” in reaction vessels from methylene chloride solution) react rapidly in the solid phase with aqueous mixtures of I − and proteins to yield iodinated proteins. Similarly applied, this reagent brings about iodination of cell membranes, although, apparently, at a somewhat lesser rate than in iodinations carried out with lactoperoxidase-glucose oxidase. The stability and sparing solubility of this chloroglycoluril in water can account for the minimal damage to proteins and living cells observed in these iodinations; further, these properties allow for elimination of the reduction step employed at the close of iodinations with soluble chloroamides such as chloramine-T.