Gramicidin S: a peptide model for protein glycation and reversal of glycation using nucleophilic amines

Shakkottai, VG and Sudha, R and Balaram, P (2002) Gramicidin S: a peptide model for protein glycation and reversal of glycation using nucleophilic amines. In: Journal-of-Peptide-Research, 60 (2). pp. 112-120.

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Abstract

Nonenzymatic glycation of proteins has been implicated in various diabetic complications and age-related disorders. Proteins undergo glycation at the N-terminus or at the ε-amino group of lysine residues. Glycation of proteins proceeds through the stages of Schiff base formation, conversion to ketoamine product and advanced glycation end products. Gramicidin S, which has two ornithine residues, was used as a model system to study the various stages of glycation of proteins using electrospray ionization mass spectrometry. The proximity of two ornithine residues in the peptide favors the glycation reaction. Formation of advanced glycation end products and diglycation on ornithine residues in gramicidin S were observed. The formation of Schiff base adduct is reversible, whereas the Amadori rearrangement to the ketoamine product is irreversible. Nucleophilic amines and hydrazines can deglycate the Schiff base adduct of glucose with peptides and proteins. Hydroxylamine, isonicotinic acid hydrazide and aminoguanidine effectively removed glucose from the Schiff base adduct of gramicidin S. Hydroxylamine is more effective in deglycating the adduct compared with isonicotinic acid hydrazide and aminoguanidine. The observation that the hydrazines are effective in deglycating the Schiff base adduct even in the presence of high concentrations of glucose, may have a possible therapeutic application in preventing complications of diabetes mellitus. Hydrazines may be used to distinguish between the Schiff base and the ketoamine products formed at the initial stages of glycation.

Item Type:	Journal Article
Publication:	Journal-of-Peptide-Research
Publisher:	John Wiley and Sons
Additional Information:	Copyright of this article belongs to John Wiley and Sons.
Keywords:	advanced glycation end products;Amadori rearrangement; gramicidin S;peptide glycation;protein glycation
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	02 Jan 2008
Last Modified:	03 Feb 2012 09:15
URI:	http://eprints.iisc.ac.in/id/eprint/12176

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