LC-MS/MS suggests that hole hopping in cytochrome c peroxidase protects its heme from oxidative modification by excess H₂O₂.

ABSTRACT: We recently reported that cytochrome c peroxidase (Ccp1) functions as a H₂O₂ sensor protein when H₂O₂ levels rise in respiring yeast. The availability of its reducing substrate, ferrocytochrome c (Cyc^II), determines whether Ccp1 acts as a H₂O₂ sensor or peroxidase. For H₂O₂ to serve as a signal it must modify its receptor so we employed high-performance LC-MS/MS to investigate in detail the oxidation of Ccp1 by 1, 5 and 10 M eq. of H₂O₂ in the absence of Cyc^II to prevent peroxidase activity. We observe strictly heme-mediated oxidation, implicating sequential cycles of binding and reduction of H₂O₂ at Ccp1's heme. This results in the incor

SUBMITTER: Kathiresan M 

PROVIDER: S-EPMC5369544 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature