Related Experiment Videos
Copper-release from yeast Cu(I)-thionein by hypothiocyanite (OSCN-)
H J Hartmann1, D Deters, U Weser
1Physiologisch-Chemisches Institut, Eberhard-Karls-Universität Tübingen, Germany.
Summary
Hypothiocyanite (OSCN-) releases copper from Cu-thionein during oxidative bursts. This copper release enhances the efficacy of activated polymorphonuclear leukocytes (PMNs) and their oxidative activity.
Area of Science:
- Biochemistry
- Metalloprotein Chemistry
- Immunology
Background:
- Activated polymorphonuclear leukocytes (PMNs) generate reactive oxygen species and hypothiocyanite (OSCN-).
- Cu-thionein, a copper-binding protein, is present during these oxidative events.
- The potential role of thiocyanate (SCN-) and its oxidized form in releasing copper to enhance oxidative bursts was investigated.
Purpose of the Study:
- To examine the reaction between yeast Cu-thionein and hypothiocyanite (OSCN-).
- To determine if OSCN- can release copper from Cu-thionein.
- To assess the impact of copper release on the oxidative activity of PMNs.
Main Methods:
- In vitro reaction of yeast Cu-thionein with OSCN-.
- Spectroscopic analysis (chiroptic and luminescence) to monitor copper-thionein integrity.
- Equilibrium dialysis to confirm copper release.
- Reductive conditions for protein reconstitution.
Main Results:
- Hypothiocyanite (OSCN-) caused significant copper release from Cu-thionein ex vivo.
- Chiroptic and luminescence signals of Cu-thionein diminished in the presence of OSCN-.
- Equilibrium dialysis confirmed the copper-releasing activity of OSCN-.
- Demetallized Cu-thionein could be reconstituted under reductive conditions.
Conclusions:
- Hypothiocyanite (OSCN-) acts as a metabolic source for transient copper release from Cu-thionein.
- This copper release may enhance the Fenton activity and efficacy of oxidative bursts generated by activated PMNs.
- Thiocyanate (SCN-) itself does not disrupt copper-thiolate bonds but its oxidized form, OSCN-, is key.