In the course of an oxidative burst oxygen free radicals and hypothioc
yanite (OSCN-), a transiently abundant derivative of thiocyanate (SCN-
), are formed in the presence of activated polymorphonuclear leukocyte
s (PMNs). At the same time Cu(I)-thionein is present and the question
arose whether or not thiocyanate and its oxidized form may transiently
release highly Fenton active copper to improve the efficacy of the ab
ove mentioned oxidative burst, Thus, the reaction of yeast Cu-thionein
with OSCN- was examined, Indeed, a release of copper from the Cu(I)-t
hiolate clusters of the protein was observed ex vivo. Both the chiropt
ic and luminescence emission signals of Cu-thionein essentially levell
ed off in the presence of a 15-fold molar excess of OSCN- expressed pe
r equivalent of thionein-copper, The effective copper-releasing activi
ty of this reagent was confirmed by equilibrium dialysis, The demetall
ized protein could be reconstituted under reductive conditions, SCN- d
id not affect the copper-thiolate bonding, It rather acts as a potent
metabolic source for the transient copper release from Cu-thionein in
the presence of activated PMNs.