Peptide and amino acid glycation: new insights into the Maillard reaction

Abstract

Nonenzymatic glycation of proteins, peptides and other macromolecules (the Maillard reaction) has been implicated in a number of pathologies, most clearly in diabetes mellitus. but also in the normal processes of aging and neurodegenerative amyloid diseases such as Alzheimer's. In the early stage, glycation results in the formation of Amadori-modified proteins. In the later stages, advanced glycation end products (AGE) are irreversibly formed from Amadori products leading to the formation of reactive intermediates, crosslinking of proteins, and the formation of brown and fluorescent polymeric materials. Although, the glycation of structural proteins has been attributed a key role in the complications of diabetes, recent attention has been devoted to the physiological significance of glycated peptide hormones. This review focuses on the physico-chemical properties of the Amadori compounds of bioactive peptides of endogenous and exogenous origin, such as Leu-enkephalin and morphiceptin, investigated under different conditions as well as on novel pathways in the Maillard reaction observed from investigating intramolecular events in ester-linked glycopeptides.

A mechanistic study on the fragmentation of peptide‐derived Amadori products

“…[24,25] In water solution, the pyranose form is the predominant one, however in organic solvents [dimethyl sulfoxide (DMSO)] the most populated form of the amino fructose moiety is the furanose. There are also suggestions that similar equilibrium is possible in gas phase.…”

Protective effects of hesperidin derivatives and their stereoisomers against advanced glycation end-products formation

“…Reactive carbonyl species, such as 3-deoxyglucosone, glyoxal (GO) and methylglyoxal (MGO), are critical intermediates formed during glycation of proteins by glucose (Thornalley et al, 1999). In the late stage, these highly reactive carbonyl compounds like GO and MGO can react very rapidly in contrast to glucose with proteins leading to the formation of a group of chemically stable substances known as advanced glycation end-products (AGEs) (Thornalley, 2005), which are often colored, fluorescent, and prone to produce crosslinks in proteins (Horvat & Jakas, 2004). AGEs, contributing to the accumulation of random damage in extracellular proteins, are known to have deleterious effects on biological function, and are associated with aging and diabetic complications, such as cataract, nephropathy, vasculopathy, proliferative retinopathy, and atherosclerosis complication in chronic diseases (Vinson & Howard, 1996).…”

Mining seed proteome: from protein dynamics to modification profiles

“…Amadori and Heyns compounds) (Heyns and Noack, 1962;Hodge, 1955) are readily involved in fragmentation already at relatively low collision energies, yielding characteristic patterns of signals in their tandem mass spectra (Frolov, Singer, and Hoffmann, 2006 . This characteristic pattern of oxonium, pyrylium and furylium ions (Horvat and Jakas, 2004) can be considered a signature of protein glycation in peptide sequence . It is important to note that these patterns are less abundant when resonance excitation is used, i.e.…”