1. Peroxidase-like activity of cytochrome b5 is triggered upon hemichrome formation in alkaline pH.
- Author
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Samhan-Arias, Alejandro K., Maia, Luisa B., Cordas, Cristina M., Moura, Isabel, Gutierrez-Merino, Carlos, and Moura, José J.G.
- Subjects
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CATALYSIS , *CYTOCHROME oxidase , *CYTOCHROMES , *CYTOCHROME b , *CHEMISTRY - Abstract
In alkaline media (pH 12) a catalytic peroxidase activity of cytochrome b 5 was found associated to a different conformational state. Upon incubation at this pH, cytochrome b 5 electronic absorption spectrum was altered, with disappearance of characteristic bands of cytochrome b 5 at pH 7.0. The appearance of new electronic absorption bands and EPR measurements support the formation of a cytochrome b 5 class B hemichrome with an acquired ability to bind polar ligands. This hemichrome is characterized by a negative formal redox potential and the same folding properties than cytochrome b 5 at pH 7. The acquired peroxidase-like activity of cytochrome b 5 found at pH 12, driven by a hemichrome formation, suggests a role of this protein in peroxidation products propagation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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