Peroxidase-like activity of cytochrome b5 is triggered upon hemichrome formation in alkaline pH

Publication date: Available online 27 September 2017 Source:Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics Author(s): K. Samhan-Arias Alejandro, Luisa B. Maia, M. Cordas Cristina, Moura Isabel, Gutierrez-Merino Carlos, J.G. Moura José In alkaline media (pH12) 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 pH7.0. 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 pH7. The acquired peroxidase-like activity of cytochrome b 5 found at pH12, driven by a hemichrome formation, suggests a role of this protein in peroxidation products propagation.

Source: Biochimica et Biophysica Acta (BBA) Proteins and Proteomics - September 28, 2017 Category: Biochemistry Source Type: research