TY - JOUR
T1 - On the formation and reactivity of compound I of the His-64 myoglobin mutants
AU - Matsui, Toshitaka
AU - Ozaki, Shin Ichi
AU - Watanabe, Yoshihito
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1997/12/26
Y1 - 1997/12/26
N2 - Myoglobin (Mb) catalyzes various two-electron oxidations; however, ferryl porphyrin cation radical equivalent to peroxidase compound I has not been identified yet. Distal histidine mutants of sperm whale Mb (His-64 → Ala, Set, and Leu) afford an apparent intermediate followed by the formation of a ferryl heme (Mb-II) in the reaction with m-chloroperbenzoic acid. Because the intermediate exhibits characteristic absorption spectrum of compound I and bears two electron oxidizing equivalents above the ferric state, we have assigned the species as compound I of myoglobin (Mb-I). Although we have recently observed compound I of the F43H/H64L Mb mutant, F43H and wild type Mb react with m-chloroperbenzoic acid to give Mb-II without any accumulation of Mb-I. The results unambiguously indicate that His-64 plays a key role in destabilizing wild type Mb-I. Furthermore, Mb-I is found to be capable of performing two-electron oxidation of styrene, thioanisole, and H2O2.
AB - Myoglobin (Mb) catalyzes various two-electron oxidations; however, ferryl porphyrin cation radical equivalent to peroxidase compound I has not been identified yet. Distal histidine mutants of sperm whale Mb (His-64 → Ala, Set, and Leu) afford an apparent intermediate followed by the formation of a ferryl heme (Mb-II) in the reaction with m-chloroperbenzoic acid. Because the intermediate exhibits characteristic absorption spectrum of compound I and bears two electron oxidizing equivalents above the ferric state, we have assigned the species as compound I of myoglobin (Mb-I). Although we have recently observed compound I of the F43H/H64L Mb mutant, F43H and wild type Mb react with m-chloroperbenzoic acid to give Mb-II without any accumulation of Mb-I. The results unambiguously indicate that His-64 plays a key role in destabilizing wild type Mb-I. Furthermore, Mb-I is found to be capable of performing two-electron oxidation of styrene, thioanisole, and H2O2.
UR - http://www.scopus.com/inward/record.url?scp=0031468071&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031468071&partnerID=8YFLogxK
U2 - 10.1074/jbc.272.52.32735
DO - 10.1074/jbc.272.52.32735
M3 - Article
C2 - 9407045
AN - SCOPUS:0031468071
VL - 272
SP - 32735
EP - 32738
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 52
ER -