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Effect of Charge‐Reversal Mutations on the Catalytic Activity of Cytochrome c Peroxidase
Author(s) -
Pearl Naw May,
Vitello Lidia B.,
Erman James E.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a272-d
Subject(s) - cytochrome c peroxidase , cytochrome c , chemistry , peroxidase , lysine , stereochemistry , cytochrome , enzyme , biochemistry , amino acid , mitochondrion
Cytochrome c peroxidase (CcP) is a yeast mitochondrial enzyme that catalyzes the reduction of hydrogen peroxide to water by ferrocytochrome c . The mechanism involves complex formation between cytochrome c and the enzyme. The driving force for complex formation between cytochrome c and CcP is largely electrostatic in nature. Both 1:1 and 2:1 cytochrome c /CcP complexes have been observed. In order to map the interaction between cytochrome c and CcP in solution, eleven different charge‐reversal mutants have been constructed by converting either aspartate or glutamate residues on the surface of CcP to lysine residues. All of the aspartate and glutamate residues are in the vicinity of the cytochrome c binding site identified by x‐ray crystallography (Pelletier and Kraut (1992) Science 258 , –1755). The effect of these charge‐reversal mutations on the steady‐state kinetic properties of CcP catalysis has been investigated. Four mutations cause large increases in the Michaelis constant for the cytochrome c interaction with CcP: D34K, D37K, E118K, and E290K. This research is supported in part by the NIH through grant R15 GM59740.