engleski

New Products of Nonenzymatic Glycation

The essential amino acid tryptophan (Trp, 1) is a building block of proteins as well as a precursor of numerous neurotransmitters and other biogenic amines involved in the pathogenesis of neurological disorders. Methylglyoxal (MG, 3) is, on the other hand, a very reactive physiological dicarbonyl formed by numerous enzymatic and non-enzymatic reactions. Its concentration is significantly elevated in diabetic patients. During the incubation of Trp and MG, depending on the reaction conditions, different products were obtained. In anaerobic conditions, 1-acyl-beta-carboline-3-carboxylic acid (4) was formed via the Pictet-Spengler reaction. However, in aerobic conditions 1-acyl-beta-carboline (5) was obtained by oxidation and decarboxylation of the previously formed tetrahydro-beta- carboline. Carboline 5 was also obtained in the reaction of tryptamine (2) and MG. Modifications of tryptophan and its metabolites with methylglyoxal could occur under physiological conditions as well as in foodstuffs during cooking and processing. Since carboline derivates have shown multiple physiological activities these reactions deserve particular interest.

nonenzymatic glycation; tryptophan; methylglyoxal

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