The aim of this study was to understand the mechanism of action through which carnosine (beta-alanyl-L-histidine) acts as a quencher of cytotoxic alpha,beta-unsaturated aldehydes, using 4-hydroxy-trans-2,3-nonenal (HNE) as a model aldehyde. In phosphate buffer solution (pH 7.4), carnosine was 10 times more active as an HNE quencher than L-histidine and N-acetyl-carnosine while beta-alanine was totally inactive; this indicates that the two constitutive amino acids act synergistically when incorporated as a dipeptide and that the beta-alanyl residue catalyzes the addition reaction of the histidine moiety to HNE. Two reaction products of carnosine were identified, in a pH-dependent equilibrium: (a) the Michael adduct, stabilized as a 5-member cyclic hemi-acetal and (b) an imine macrocyclic derivative. The adduction chemistry of carnosine to HNE thus appears to start with the formation of a reversible alpha,beta-punsaturated imine, followed by ring closure through an intra-molecular Michael addition. The biological role of carnosine as a quencher of alpha,beta-unsaturated aldehydes was verified by detecting carnosine-HNE reaction adducts in oxidized rat skeletal muscle homogenate. (C) 2002 Elsevier Science (USA). All rights reserved.
Carnosine is a quencher of 4-hydroxy-nonenal: through what mechanism of reaction? / G. Aldini, M. Carini, G. Beretta, S. Bradamante, R. Maffei Facino. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - 298:5(2002), pp. 699-706.
Titolo: | Carnosine is a quencher of 4-hydroxy-nonenal: through what mechanism of reaction? |
Autori: | ALDINI, GIANCARLO (Primo) CARINI, MARINA (Secondo) |
Settore Scientifico Disciplinare: | Settore CHIM/08 - Chimica Farmaceutica |
Data di pubblicazione: | 2002 |
Rivista: | |
Tipologia: | Article (author) |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1016/S0006-291X(02)02545-7 |
Appare nelle tipologie: | 01 - Articolo su periodico |