Influence of viscosity on mechanism and products of radical reactions of kynurenic acid and tryptophan

E. D. Savina, Yu P. Tsentalovich, P. S. Sherin

Research output: Contribution to journalArticlepeer-review

Abstract

Under UV-A light and anaerobic conditions, the photodegradation of kynurenic acid and tryptophan significantly decreases with an increase in the viscosity of the medium without significant changes in the composition of the formed products. The recombination products of tryptophan radicals (covalently linked dimeric forms) exhibit the most pronounced decrease. The observed effects are due to restrictions of mobility of the formed radicals and a longer stay in the radical cage as compared to the behavior in aqueous solutions. This leads to an increase in the efficiency of the back electron transfer with the restoration of the initial reagents, which is the main decay pathway for the radicals. The backside of cage effect is an increase in quantities of covalently bound adducts of kynurenic acid and tryptophan. In the case of a living cell, similar changes in the composition of the radical reaction products can be expected.

Original languageEnglish
Pages (from-to)2339-2346
Number of pages8
JournalRussian Chemical Bulletin
Volume70
Issue number12
DOIs
Publication statusPublished - Dec 2021

Keywords

  • back electron transfer
  • free radicals
  • kynurenic acid
  • photochemical reaction
  • quantum yield
  • tryptophan
  • water—glycerol mixtures

OECD FOS+WOS

  • 1.04 CHEMICAL SCIENCES

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