Pulse radiolytic measurement of redox potentials: the tyrosine and tryptophan radicals.
With the technique of pulse radiolysis we have measured the redox midpoint potentials of the tryptophan side chain neutral indolyl radical (1.05 +/- 0.01 V vs NHE, pH 7.0 and 25 degrees C) and the tyrosine side chain neutral phenoxy radical (0.94 +/- 0.01 vs NHE, pH 7.0 and 25 degrees C). These potentials were obtained by using a variety of inorganic reference compounds in both kinetic and equilibrium protocols. We compare these results with others already in the literature, and we also present data useful in establishing a pulse radiolysis redox reference scale over the range 0.42-1.28 V.
Department of Chemistry, Ohio State University, Columbus 43210.
M R
MR
DeFelippis
C P
CP
Murthy
M
M
Faraggi
M H
MH
Klapper
D005609:Free Radicals; D007700:Kinetics; D010084:Oxidation-Reduction; D011675:Pulse Radiolysis; D014364:Tryptophan; D014443:Tyrosine
D005609:Free Radicals; D014443:Tyrosine; D014364:Tryptophan