Ufnalska I, Drew SC, Zhukov I, Szutkowski K, Wawrzyniak UE, Wróblewski W, Frączyk T, Bal W. Intermediate Cu(II)-Thiolate Species in the Reduction of Cu(II)GHK by Glutathione: A Handy Chelate for Biological Cu(II) Reduction.
Inorg Chem 2021;
60:18048-18057. [PMID:
34781677 PMCID:
PMC8653159 DOI:
10.1021/acs.inorgchem.1c02669]
[Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
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Gly-His-Lys (GHK)
is a tripeptide present in the human bloodstream
that exhibits a number of biological functions. Its activity is attributed
to the copper-complexed form, Cu(II)GHK. Little is known, however,
about the molecular aspects of the mechanism of its action. Here,
we examined the reaction of Cu(II)GHK with reduced glutathione (GSH),
which is the strongest reductant naturally occurring in human plasma.
Spectroscopic techniques (UV–vis, CD, EPR, and NMR) and cyclic
voltammetry helped unravel the reaction mechanism. The impact of temperature,
GSH concentration, oxygen access, and the presence of ternary ligands
on the reaction were explored. The transient GSH-Cu(II)GHK complex
was found to be an important reaction intermediate. The kinetic and
redox properties of this complex, including tuning of the reduction
rate by ternary ligands, suggest that it may provide a missing link
in copper trafficking as a precursor of Cu(I) ions, for example, for
their acquisition by the CTR1 cellular copper transporter.
Gly-His-Lys (GHK) is a human bioactive
tripeptide thought
to be activated by Cu(II) binding, but little is known about the molecular
aspects of its action. UV−vis, circular dichroism (CD), EPR,
and NMR spectroscopies, and cyclic voltammetry were used to examine
the reduction of Cu(II)GHK with glutathione (GSH), the most abundant
biological thiol. A semistable GSH-Cu(II)GHK reaction intermediate
was discovered, with properties suitable for delivering Cu(I) to biological
transport proteins.
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