Cytochrome c551 from Pseudomonas aeruginosa has been studied by differential pulse voltammetry and cyclic voltammetry at the 4,4′-bipyridine activated gold electrode within the pH range 4.3-10.9. The redox potential U′0 varies from ca. 0.32 to 0.26 V (versus n.h.e.). Spectrophotometric measurements show the disappearance of the 690 nm band, an enhancement of the 408 nm band, and the appearance of an additional band at 551 nm when the pH is increased from 6 to 11, but without total reversibility when the pH is returned to the initial value. The existence of two forms of cytochrome c551 (iron-methionine bonded and iron-methionine unbonded heme) is proposed, and a comparison with horse heart cytochrome c is given. © 1983 Elsevier Sequoia S.A.
Haladjian, J., & Bianco, P. (1983). Effect of pH on the electrochemical and spectrophotometric properties of Pseudomonas aeruginosa cytochrome c551: A comparison with horse heart cytochrome c. Journal of Electroanalytical Chemistry, 156(C), 319–326. https://doi.org/10.1016/S0022-0728(83)80683-4