TY - JOUR
T1 - Reactivity of manganese peroxidase
T2 - Site-directed mutagenesis of residues in proximity to the porphyrin ring
AU - Ambert-Balay, Katia
AU - Dougherty, Mike
AU - Tien, Ming
N1 - Funding Information:
This investigation was supported in part by U.S. Department of Energy Grant DE-FG02-87ER13690.
PY - 2000/10/1
Y1 - 2000/10/1
N2 - The purpose of this study was to determine the effect of heme pocket hydrophobicity on the reactivity of manganese peroxidase. Residues within 5 Å of the heme active site were identified. From this group, Leu169 and Ser172 were selected and mutated to Phe and Ala, respectively. The mutant proteins were then characterized by steady-state kinetics. Whereas the Leu169Phe mutation had little, if any, effect on activity, the Ser172Ala mutation decreased k(cat) and also the specificity constant (k(cat)/K(m)) for Mn2+, but not H2O2. Transient-state studies indicated that the mutation affected only the reactions of compound II. These results indicate that compound II is the most sensitive to changes in the heme environment. (C) 2000 Academic Press.
AB - The purpose of this study was to determine the effect of heme pocket hydrophobicity on the reactivity of manganese peroxidase. Residues within 5 Å of the heme active site were identified. From this group, Leu169 and Ser172 were selected and mutated to Phe and Ala, respectively. The mutant proteins were then characterized by steady-state kinetics. Whereas the Leu169Phe mutation had little, if any, effect on activity, the Ser172Ala mutation decreased k(cat) and also the specificity constant (k(cat)/K(m)) for Mn2+, but not H2O2. Transient-state studies indicated that the mutation affected only the reactions of compound II. These results indicate that compound II is the most sensitive to changes in the heme environment. (C) 2000 Academic Press.
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U2 - 10.1006/abbi.2000.2000
DO - 10.1006/abbi.2000.2000
M3 - Article
C2 - 11051101
AN - SCOPUS:0034306854
SN - 0003-9861
VL - 382
SP - 89
EP - 94
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -