1 research outputs found
Boron-Doped Diamond Electrodes for the Electrochemical Oxidation and Cleavage of Peptides
Electrochemical oxidation of peptides
and proteins is traditionally
performed on carbon-based electrodes. Adsorption caused by the affinity
of hydrophobic and aromatic amino acids toward these surfaces leads
to electrode fouling. We compared the performance of boron-doped diamond
(BDD) and glassy carbon (GC) electrodes for the electrochemical oxidation
and cleavage of peptides. An optimal working potential of 2000 mV
was chosen to ensure oxidation of peptides on BDD by electron transfer
processes only. Oxidation by electrogenerated OH radicals took place
above 2500 mV on BDD, which is undesirable if cleavage of a peptide
is to be achieved. BDD showed improved cleavage yield and reduced
adsorption for a set of small peptides, some of which had been previously
shown to undergo electrochemical cleavage C-terminal to tyrosine (Tyr)
and tryptophan (Trp) on porous carbon electrodes. Repeated oxidation
with BDD electrodes resulted in progressively lower conversion yields
due to a change in surface termination. Cathodic pretreatment of BDD
at a negative potential in an acidic environment successfully regenerated
the electrode surface and allowed for repeatable reactions over extended
periods of time. BDD electrodes are a promising alternative to GC
electrodes in terms of reduced adsorption and fouling and the possibility
to regenerate them for consistent high-yield electrochemical cleavage
of peptides. The fact that OH-radicals can be produced by anodic oxidation
of water at elevated positive potentials is an additional advantage
as they allow another set of oxidative reactions in analogy to the
Fenton reaction, thus widening the scope of electrochemistry in protein
and peptide chemistry and analytics