M. Erk et B. Raspor, EVALUATION OF CADMIUM-METALLOTHIONEIN STABILITY-CONSTANTS BASED ON VOLTAMMETRIC MEASUREMENTS, Analytica chimica acta, 360(1-3), 1998, pp. 189-194
A voltammetric study on the binding properties of the commercially ava
ilable rabbit liver metallothionein (MT) Sigma M 7641 for cadmium ions
was performed. The capacity of metallothionein to complex cadmium and
the stability constants of Cd-T complex (T denotes the apoprotein or
thionein molecule) have been determined from the direct titration of t
he defined MT concentration with the standard CdCl2 solution in 0.59 M
sodium chloride medium at pH 7.9 and 2.0. At pH 7.9 the formation of
the Cd-T complex has been followed measuring the specific anodic signa
l height of the complex. Stability constants of Cd-T have been evaluat
ed from the experimental data using three different procedures. The ca
lculated apparent stability constants K=(7.6+/-0.2).10(8) dm(3) mol(-1
) of Cd-T complex in 0.59 M NaCl at pH 7.9 and 25 degrees C indicate t
hat under the given experimental conditions all the three procedures a
re equally applicable. (C) 1998 Elsevier Science B.V.