HIGH-VALENT Cr, Mn, AND Fe SPECIES - Oxidation of Amino Acids, Peptides, and Proteins: Kinetics and Mechanism - page 336

(a)
(b)
Figure 6.32. (A) Proposed mechanism for reaction of [Fe IV (O)(N4Py)] 2+ with Ac-Trp-
NHtBu (A) and Ac-Tyr-NHtBu (B) (adapted from Abouelatta et al. [334] with the
permission of the American Chemical Society).
intermediate, [Fe III (OH)(N4Py)] 2+ , with a lower limit rate constant of
1 × 10 4 /M/s (Eq. 6.99) [345]. The intermediate reacted with another molecule
of GSH to yield a green intermediate, [Fe III (SG)(N4Py)] 2+ (Eq. 6.100), which
was characterized by uV-vis, EPR, and high-resolution time-of-flight mass
spectrometry (HR-ToF-MS). The green intermediate could not be produced
with other thiols. The value of ε 650 = 1870/M/cm was calculated for the