Unravelling the Occurrence of Mediator-Blood Protein Interactions via the Redox Catalysis of the Physiological Gasotransmitter Hydrogen Sulfide

摘要

Ferrocenemethanol is employed as an aqueous, homogeneous redox mediator for hydrogen sulfide. The reaction is seen to follow an EC’ mechanism over the range 6?pH?9, with bisulfide reacting four times more rapidly than hydrogen sulfide. In the presence of 10 vol.% haemolysed blood, greater concentrations of sulfide (as H2S or as HS-) are required to achieve the same degree of redox catalysis, compared with the absence of the blood proteins, at both pH 7 and pH 9. It is suggested that this phenomenon derives from a ferroceneme- thanol/blood protein interaction, which is first titrated by the sulfide species. This can give rise to a titration-based electro- analytical assay for sulfide in blood, whilst being important for blood-based electrochemical bioassays involving hydrophilic ferrocene derivatives.