G. Bordin et al., CHROMATOGRAPHIC CHARACTERIZATION OF A HEXAPEPTIDE CONTAINING 3 THIOL-GROUPS, INTRINSIC TO THE METALLOTHIONEIN STRUCTURE, Chromatographia, 39(3-4), 1994, pp. 146-154
The hexapeptide Lys-Cys-Thr-Cys-Cys-Ala [56-61] MT I is a molecule int
rinsic to the metallothionein structure. Its chromatographic behaviour
on a reversed-phase column, using electrochemical detection has been
studied in order to get a better understanding of its chemical stabili
ty under various conditions. The chromatogram of the peptide consists
of two peaks. The optimization procedure for their separation is prese
nted and a hydrodynamic voltammogram has been generated. The relative
proportion of the two peaks can vary with experimental conditions and
is clearly dependent of the peptide concentration. Following the vario
us experiments to which the peptide was submitted, namely elution afte
r air oxidation, under inert atmosphere, in basic pH, after addition o
f an oxidizing agent (H2O2) and after addition of a reducing agent (2-
mercaptoethanol), a reaction scheme was suggested: transformations of
the reduced hexapeptide (three free thiol groups) into - as a first st
ep - its intramolecular oxidized form (one SS bond, one free SH) and t
hen into - as a second step - the fully oxidized dimeric form (no more
free SH). Electrochemical detection allows a quantitative follow-up o
f the thiol oxidation and hence, of the disappearance of the reduced p
eptide.