Biologically active principles, chemical elucidation

Electrochemistry provides a powerful tool for elucidating the pH-dependent redox mechanisms of coordination complexes. In principle, any electrochemically active chemical (or biological) system may exhibit pH-dependent reduction potentials, if the concomitant pH-dependent process occurs on the same timescale as electron transfer. While the pH-dependent process is ultimately chemical in nature (i.e., involves bond breaking and/or bond making), the phenomenon that perturbs the redox center and alters the reduction potential may be electronic, structural (e.g., a conformational change), or environmental (e.g., changes in solvation), and often will be some ill-defined combination of these factors. ... 

---