P 029 - Free radical transformations of hydroxyl-containing amino acids and related compounds in aqueous solutions

Abstract

It is well known that reactive oxygen species (ROS), generated via various enzymatic and non-enzymatic pathways, can cause the damage of biomolecules. It was established that ROS, interacting with amino acids, initiated mainly their deamination and decarboxylation, the probability of which was largely determined by the molecule structures and their forms in the solutions. Using γ-irradiation for • OH generation we have shown that serine (Ser), threonine (Thr) and related dipeptides as well as glucosamine (GlcN) and 1-amino-2-propanol undergo • OH-induced carbon skeleton destruction in aqueous solutions. It was shown that destruction of Ser and Thr proceeded via formation of N-centered radicals of starting compounds. As a result of such reactions glycine and formaldehyde (or acetaldehyde) were formed. The non-enzymatic free radical Ser conversion, resulting in the formation of glycine and formaldehyde, is similar to the Ser bioconversion driven by serine hydroxymethyltransferase. Among radiolysis products of Ser and Thr in oxygenated solutions glyoxal and methylglyoxal, which are known to possess high toxicity, have been found. The obtained data are recommended to consider during estimation of ROS-induced pathophysiological processes involving such biomoleculs as Ser, Thr and the corresponding peptides as well as GlcN, and, possibly, their complex macromolecular derivatives.