The formation of yeast cytochrome c peroxidase (CcP) compound I has been recognized for many years to be associated with formation of two protein-centered radicals. One of these radical sites is located at Trp191 and is directly involved in catalytic oxidation of ferrocytochrome c (Sivaraja, M., Goodin, D. B., Smith, M., Hoffman, B. M. (1989) Science 245, 738-740). The second radical has been proposed to arise from one or more tyrosyl residues of CcP. However, the tyrosyl residue (or residues) capable of forming this radical has not been identified, and the functional role of this radical remains poorly understood. In the present work, this issue has been addressed through the combined use of the spin-trapping reagent 2-methyl-2-nitrosopropane and peptide mapping by electrospray mass spectrometry to identify Tyr39 and Tyr153 as two tyrosyl residues that are capable of forming radical centers upon reaction of CcP with hydrogen peroxide. The implications of this observation to the catalytic mechanism of CcP are addressed with reference to the three-dimensional structure of CcP.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|