title: Electrochemical investigation of redox thermodynamics of immobilized myoglobin: ionic and ligation effects.
abstract: In this study, we investigated redox thermodynamics of myoglobin as well as the ionic (phosphate ions) and ligation (imidazole) effects via a dynamic electrochemical approach. We employed a previously established system that features nonmediated, direct electrochemistry of myoglobin and myoglobin in an immobilized state (i.e., diffusionless electrochemistry). Thermodynamics parameters were obtained by measuring redox potential (E degrees ') of myoglobin at varied temperature (T), in the presence and in the absence of specific ions or axial ligands. As a step further, we evaluated contributions from allosteric effect and axial iron ligation by partitioning E degrees ' changes into entropic and enthalpic terms. Compensation phenomena between the entropic and enthalpic changes were observed in all these cases. On the basis of these studies, we also correlated these phenomena to possible structural variations.
authors.affiliation: Department of Biochemistry and National Key Laboratory of Pharmaceutical, Biotechnology, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Liu
authors.forename: Yinxi
authors.initials: Y
authors.lastname: Huang
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Fan
authors.forename: Chunhai
authors.initials: C
authors.lastname: Fan
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D000494:Allosteric Regulation; D004563:Electrochemistry / Q000379:methods*; D007477:Ions; D009211:Myoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D013816:Thermodynamics
chemical_list: D007477:Ions; D009211:Myoglobin