Cm. Hosten et al., RESONANCE RAMAN-SPECTROSCOPY OF THE CATALYTIC INTERMEDIATES AND DERIVATIVES OF CHLOROPEROXIDASE FROM CALDARIOMYCES-FUMAGO, The Journal of biological chemistry, 269(19), 1994, pp. 13966-13978
Near-ultraviolet resonance Raman spectra of chloroperoxidase derivativ
es and high valent intermediates show frequencies that can be systemat
ically assigned. In accord with previous observations of low nu(4) fre
quencies for the ferric enzyme, and quite low nu(4) frequencies for th
e ferrous enzyme, low nu(4) frequencies are observed for ferryl compou
nd II and several ferric derivatives. Resonance Raman spectra of chlor
operoxidase compound I feature upshifted nu(2), nu(11), and nu(37) fre
quencies and other characteristics that argue for a (2)A(1u) in prefer
ence to a (2)A(2u) ground state for the porphyrin pi-cation radical. A
moderately intense anomalously polarized band is observed at a freque
ncy typical for octaethylporphyrin pi-cation radicals, which have been
previously assigned as the (2)A(1u) radical type. Similar resonance R
aman spectral attributes are observed for horseradish peroxidase compo
und I, supporting a (2)A(1u) symmetry state assignment for this specie
s also. A (2)A(1u) symmetry state assignment for chloroperoxidase and
horseradish peroxidase compounds I is consistent with the beta pyrrole
substituent pattern of the protoporphyrin hemes found in these enzyme
s.