Integration methods for enzymatic reactions were applied to
transducer response vs. time curves which exhibit maxima, minima or
inflections. The difference between the integral of the time
dependent response and the initial response, often zero, is related
to the initial enzyme activity or substrate concentration. Fluorescence response curves which exhibit a maximum due to pre- and postfilter
effects at elevated concentrations of a time dependent fluorescence indicator species result in integrals which may not be
unique to one analyte concentration. It was found that augmenting
the integral data with the time of the maximum permitted correlation
of each integral with a unique analyte concentration or enzyme
activity. Integrals of response curves which exhibit minima also
correlate with unique analyte concentrations. At increased concentration of analyte, however, the minimum may broaden into a minimum
plateau and the time of the minimum may supplement the integral data as a more sensitive measure of analyte concentration. Integrals of
enzymatic response curves with inflection points correlate with
unique analyte concentrations.
Integration methods were applied to both real and ideal systems. Theoretical rate equations were used to generate families of
idealized response curves exhibiting maxima, minima and inflections. Curves were generated at either fixed initial substrate
concentration with variable enzyme activity or at fixed initial
enzyme activity with variable substrate concentration. Difference
integrals were calculated and plotted as a function of initial substrate concentration or initial enzyme activity.
Enzymatic analyses were also performed using systems which
produce families of response curves exhibiting maxima, minima and
inflections. Difference integrals were calculated for these curves
and related to initial enzyme activity or substrate concentration
