Sulfhydryls with Ethylenimine

Hgure 83 The small compound ethyienimine can react with sulfhydryls to form aminoethyl derivatives. 

Ethyienimine may be used to introduce additional sites of tryptic cleavage for protein structural studies. In this case, complete sulfhydryl modification is usually desired. Proteins are treated with ethyienimine under denaturing conditions (6—8 M guanidine hydrochloride) in the presence of a disulfide reductant to reduce any disulfide bonds before modification. Ethyienimine may be added directly to the reducing solution in excess (similar to the procedure for Aminoethyl-8 described previously) to totally modify the — SH groups formed. 

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