Unusual result of modification of anemonotoxin RTX-III by malonaldehyde
The modification of the arginine residues of neurotoxin RTX-III fromRadianthus macrodactylus with malonaldehyde led to the formation of a derivative with a maximum in the UV spectrum at 340 nm in place of the expected Nδ-(pyrimidin-2-yl)ornithine with absorption at 315 nm. On the basis of chemical transformations and the results of absorption spectroscopy, it has been concluded that the product obtained was an intermediate of the reaction — a Schiff's base. It has been shown that the stabilization of the reactive intermediate is due to the influence of steric factors. The further conversion of the toxin derivative taking place in neutral and alkaline media has been investigated; it is connected with a rearrangement of the malonaldehyde residue of the enol-enamine type.
KeywordsOrganic Chemistry Arginine Schiff Absorption Spectroscopy Ornithine
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