Reversible Enzymatic Switching of the Oxidation State of a EuIII/II Complex Controls Relaxivity
Euan T Sarson1, Saul M Cooper1, Adam C Sedgwick1
1Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom.
None:
We show that europium trisbipyridyl cryptate exhibits an electrochemically reversible EuIII/II redox couple at -360 mV vs the standard hydrogen electrode (SHE) and is susceptible to reduction or oxidation by a range of redox enzymes or biological small molecule redox agents. Modulation of the europium oxidation state can be used to achieve dramatic changes in the T1 relaxation time of bulk water in solutions containing these complexes: in the reduced form, the complex exhibits high relaxivity (3.08 mM-1 s-1 at 499.9 MHz) comparable with that of commercial MRI contrast media, while the oxidized form has negligible relaxivity, illustrating the scope for application in imaging reducing environments in biological systems.
More Related Videos
08:34A Dual-Functional Electroactive Filter Towards Simultaneously SbIII Oxidation and Sequestration
Published on: December 5, 2019
13:21Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
Related Concept Videos
Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Redox Titration: Other Oxidizing and Reducing Agents
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex,...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
