PEGylation by Click Chemistry

PEGylation of proteins. Thus, proteins which have been incorporated with azido-containing non-natural amino acids react with mPEG-alkynes affording triazole linkages, as depicted in Equation 3.36 [239]. 

In a closely related method, the genetically introduced para-azidophenylalanine residue was used to achieve the site-specific conjugation of SOD by means of a [3+2] cycloaddition reaction with mPEG-propargyl amine 69 (Equation 3.39) [250]. 

This method has been used in the PEGylation of modified CalB, and it has been demonstrated that the conjugation reactions proceed faster than the analogue processes catalyzed by copper [252], 

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