Document Detail

Anchimeric assistance effect on regioselective hydrolysis of branched PEGs: a mechanistic investigation.
MedLine Citation:
PMID:  15351387     Owner:  NLM     Status:  MEDLINE    
Branched poly(ethylene glycols) (PEG2) are nowadays widely used for protein and peptides bioconjugation, for their favourable properties (such as the ability to protect the protein surface in an 'umbrella like' fashion). The discovery that mPEG(2)-LysMetbeta AlaOEt lost one mPEG chain during standard base-catalysed ester hydrolysis conditions prompted us to investigate the hydrolytic stability of such systems and the mechanism involved in the PEG chain loss. A series of branched PEGs, substituted with different aminoacids and dipeptides, have been prepared to test the influence of steric hindrance, chain lengths, ramification and Lys-AA amide substitution on hydrolysis. Unexpected results reveal an anchimeric assistance of the Lys-AaA amide proton to the hydrolysis of the carbamoyl moiety joining mPEG to the alpha-amino group of lysine through the formation of an hydantoin system.
Andrea Guiotto; Mirta Canevari; Michela Pozzobon; Stefano Moro; Piero Orsolini; Francesco M Veronese
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Bioorganic & medicinal chemistry     Volume:  12     ISSN:  0968-0896     ISO Abbreviation:  Bioorg. Med. Chem.     Publication Date:  2004 Oct 
Date Detail:
Created Date:  2004-09-07     Completed Date:  2005-04-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9413298     Medline TA:  Bioorg Med Chem     Country:  England    
Other Details:
Languages:  eng     Pagination:  5031-7     Citation Subset:  IM    
Dipartimento di Science Farmaceutiche, Via Marzolo, 5, 35131 Padova, Italy.
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MeSH Terms
Amino Acids / chemistry
Dipeptides / chemistry
Drug Stability
Lysine / chemistry*
Polyethylene Glycols / chemistry*
Reg. No./Substance:
0/Amino Acids; 0/Dipeptides; 0/Polyethylene Glycols; 56-87-1/Lysine

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