Ethylenimine, cleavage

Ethylenimine 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 ethylenimine under denaturing conditions (6-8 M guanidine hydrochloride) in the presence of a disulfide reductant to reduce any disulfide bonds before modification. Ethylenimine 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. 

Ethylene oxide reacts with hydrogen sulfide at 45-60° to produce -hydroxyethyl sulfide in 90% yield. The reaction can be stopped at the mercaptan stage with excess hydrogen sulfide. Analogous reactions of ethylenimine and ethylene sulfide produce both the sulfides and substituted mercaptans. Cleavage of the ethylene oxide ring by mercaptans gives /S-hydroxyethyl alkyl sulfides in 70-90% yields. ... 

References to the following reactions of ethylenimine are to be found in areview. cleavage by acids (reversal of formation) hydrolysis in weakly acidic solution reaction with thiols, for example with cysteine to give (1) reaction with carbon disulfide to form 2-mercaptothiazoline (2). The reaction of ethylenimine with... 

Poly(ethylenimine-co-L-lactamide-co-succinamide) was synthesized as a copolymer of 1.2 kDa LMW-PEI and 1 kDa oligo(L-lactic acid-co-succinic acid) [ 123]. The resulting copolymer P(El-co-LSA) (8 kDa) forms small poly-plexes (ISOnm) with a positive surface charge of + 18 mV. Similar to LMW PEI, the copolymer exhibited a low toxicity profile P(EI-co-LSA) degrades via base-catalyzed hydrolytic cleavage which is higher at pH 7 than at pH 5. 

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