Comparative Lipase-Catalyzed Hydrolysis of Ethylene Glycol Derived Esters. The 2-Methoxyethyl Ester as a Protective Group in Peptide and Glycopeptide Synthesis

Abstract

Comparison of the lipase-catalyzed cleavage of polar esters derived from ethylene glycol proved 2-methoxyethyl (ME) esters most favorable protecting groups for the carboxylic function of peptides and glycopeptides. They combine high substrate acceptance and high yields of hydrolysis with favorable physiochemical properties and advantageous solubility. The application of this polar ester as protecting group was extended to N-glycosylated amino acids and N-glycopeptides. The selective removal of ME esters by lipases was achieved under mild conditions (pH 7.0 and 37°C), leaving all other linkages including peptide bonds and other ester protecting groups unaffected.