The Maillard reaction in vivo

Abstract

The Maillard or browning reaction between reducing sugars and protein contributes to the chemical deterioration and loss of nutritional value of proteins during food processing and storage. This article presents and discusses evidence that the Maillard reaction is also involved in the chemical aging of long-lived proteins in human tissues. While the concentration of the Amadori adduct of glucose to lens protein and skin collagen is relatively constant with age, products of sequential glycation and oxidation of protein, termed glycoxidation products, accumulate in these long-lived proteins with advancing age and at an accelerated rate in diabetes. Among these products are the chemically modified amino acids, N epsilon-(carboxymethyl)lysine (CML), N epsilon-(carboxymethyl)hydroxylysine (CMhL), and the fluorescent crosslink, pentosidine. While these glycoxidation products are present at only trace levels in tissue proteins, there is strong evidence for the presence of other browning products which remain to be characterized. Mechanisms for detoxifying reactive intermediates in the Maillard reaction and catabolism of extensively browned proteins are also discussed, along with recent approaches for therapeutic modulation of advanced stages of the Maillard reaction.

Formation Pathways for Lysine-Arginine Cross-links Derived from Hexoses and Pentoses by Maillard Processes

“…This was completely unexpected since from the substitution pattern of the six-membered ring in pentosinane 10 and the seven-membered ring in glucosepane 9, 3-deoxyosones would constitute reasonable precursors. Both 3-DOP 8 and 3-DOG 7 were shown to be at most a minor source for pentosidine 11 (31)(32)(33). This is easily understood now that pentosinane 10 has been established as the precursor of pentosidine 11 (see below).…”

Pharmacological reversal of advanced glycation end-product-mediated protein crosslinking

“…However, development of improved agents for preventing or reversing this process in vivo has been hampered by a lack of detailed knowledge of the chemical nature of the principal crosslinking structures. The crosslinking structures identified to date are thought on the basis of chemical considerations and spectroscopic data to constitute only a small fraction of the AGE crosslinking which occurs in vivo, with the major crosslinking structures still unidentified [5].…”

Interplay Between Oxidative and Carbonyl Stresses: Molecular Mechanisms, Biological Effects and Therapeutic Strategies of Protection

“…Oxidation reactions and ROS have been shown to be involved and frequently accelerate the advanced glycation process (Tessier, 2010). That is why "glycoxidation" term has been introduced (Dyer et a., 1991).…”