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VOL. 75 (1), 25-41, 2009 MONO AND BIEXPONENTIAL IN...

2. THEORETICAL MODEL

This is the reaction studied:

PM + Q ? PQ + M

P = Anti-Insulin antibody immobilised on the tube wall.
M = 125I-Insulin.
PM = Radioactive immunocomplex.
Q = Insulin.
PQ = Non-radioactive immunocomplex.

The treatment of the reaction kinetic model was exposed in a pa-
per published earlier (24). As it appeared there, the activity of PM in
cpm (z) varies over time according to the equation:

z = ze+ (z0-ze)(exp(-t (z0qek’1/(z0-ze)+(z0-ze)(k’-1-k’1)))) Eq. 1

z = Activity of PM in cpm, z0 = initial value of z, ze = z value in the
equilibrium, q = Q concentration (pmol/L), e= Conversion factor con-

centration-activity, k’1 = rate constant for the forward reaction, k’-1 =
rate constant for the reverse reaction, z0qek’1/(z0-ze)+(z0-ze)(k’-1-k’1) =
Apparent rate constant.

Or, for two processes:

z = ze1+ (z01-ze1)(exp(-t (z01k’1+qe (k’-1-k’1)))) + ze2 + (z02-ze2)(exp(-t

(z02k’2+qe (k’-2-k’2)))) Eq. 2

3. MATERIALS AND METHODS

3.1. Instruments

ILKB Gammamaster Automatic Gamma Counter.
Brookfield DV–II digital viscosimeter. Viscosity measurements
were performed at 60 rpm with a UL ADAPTER at room temperature.

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