Nitric oxide rapidly scavenges tyrosine and tryptophan radicals

J. P. Eiserich, J. Butler, A. Van der Vliet, Carroll E Cross, B. Halliwell

Research output: Contribution to journalArticlepeer-review

136 Scopus citations


By utilizing a pulse-radiolytic technique, we demonstrate for the first time that the rate constant for the reaction of nitric oxide (.NO) with biologically relevant tyrosine and tryptophan radicals (Tyr. and Trp. respectively) in amino acids, peptides and proteins is of the order of (1-2) x 109 M-1·s-1. We also show that .NO effectively interferes with electron-transfer processes between tryptophan and tyrosine residues in proteins subjected to pulse radiolysis. The near diffusion-controlled rates of these reactions, coupled with the increasingly recognized role of protein radicals in enzyme catalysis and oxidative damage, suggest that Tyr. and Trp. are likely and important targets for .NO generated in vivo.

Original languageEnglish (US)
Pages (from-to)745-749
Number of pages5
JournalBiochemical Journal
Issue number3
StatePublished - 1995

ASJC Scopus subject areas

  • Biochemistry


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