Chemical Pathways of the Maillard Reaction

In Vitro Kinetic Studies of Formation of Antigenic Advanced Glycation End Products (AGEs)

“…The absolute rates of AGE formation appeared higher with human methemoglobin than with the other two proteins, 2 but the compounds revealed largely similar inhibition trends (data not shown). Of the vitamin B 6 derivatives, pyridoxamine showed the greatest inhibition at concentrations of 3 mM and above when compared with pyridoxal phosphate, pyridoxal, and pyridoxine. In the case of the B 1 compounds, the inhibitory effects were more similar to the BSA inhibition trends than to RNase.…”

“…Inhibition by Vitamin B 6 Derivatives of the Overall Kinetics of AGE Formation-The inhibitory effects of the B 1 and B 6 vitamins on the kinetics of antigenic AGE formation were evaluated by polyclonal antibodies specific for AGEs. 3 Our initial inhibition studies were carried out on the glycation of bovine ribonuclease A (RNase) in the continuous presence of 0.05 M ribose.…”

“…Inhibition by Vitamin B 6 Derivatives of the Kinetics of PostAmadori Ribose AGE Formation-In the interrupted glycation assays for following post-Amadori AGE formation, kinetics were followed by incubating isolated Amadori intermediates of either RNase or BSA at 37°C in absence of free or reversibly bound ribose. Ribose sugar that was initially used to prepare the intermediates was removed by cold dialysis after an initial glycation period of 24 h. Following this interruption, AGE formation resumes and the kinetics of this post-Amadori AGE formation is quite rapid (half-times of about 10 h) in absence of inhibitors (39).…”

“…5 In terms of the classical pathway of glycation (Scheme 3), aminoguanidine could decrease the rate of initial Schiff base formation by complexing the acyclic free aldehyde forms of the sugars. 6 Inhibition through formation of such an aminoguanidine-sugar interaction was first advanced by Khatami et al (32), and recently a glucose-aminoguanidine adduct was produced, isolated, and structurally characterized by Hirsch et al (33).…”

“…Nonenzymatic protein glycation (glucosylation or glycosylation) by glucose is a complex cascade of condensations, rearrangements, fragmentations, and oxidative modifications that lead to poorly characterized heterogeneous products often collectively termed Advanced Glycation End Products or AGEs 1 (1)(2)(3)(4)(5)(6)(7). These very slow Maillard reactions are believed to underlie the pathogenesis of diabetes (8 -15) and possibly neurodegenerative amyloidal diseases such as Alzheimer's (16 -21).…”