Investigation of Catalytic Properties of Immobilized Enzymes and Cells by Flow Microcalorimetry - Advances in Biochemical Engineering Biotechnology - page 77

A B

Fig. 4. Conversion of thermometric data

produce the same thermometric signal at steady state.This assumption enables
transformation of the signal-time dependence to substrate-concentration-time
dependence. Determination of this dependence at one point is indicated in
Fig. 4. The calibration dependence shown in Fig. 4A is, in effect, the same as
the dependence of the steady state signal on substrate concentration shown in
Fig. 2.After establishing the dependence of substrate concentration on time,the
reaction rate in the column can be calculated using Eq. (22) in the form

V T e

v obs =v 0 (23)

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V C
where the substrate concentration at time zero,v 0 ,is derived from the obtained
subtrate-time dependence. The determined reaction rate in the column, v obs ,is
linked to the initial thermometric signal, D T r . Using these values the trans-

formation parameter a is calculated from Eq. (21)

DT r

a = (24)

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v obs
In the following section examples are given that illustrate the application of the
principles introduced above to the study of the properties of immobilized bio-
catalysts.

5
Applications of the Method

5.1
Investigation of Enzyme Kinetics

In spite of the evident advantages of flow microcalorimetry, this technique has
been used in only a few experimental investigations of enzyme kinetics.Several
references dealing with this subject are listed in Table 1.
Different aspects of the characterization of the properties of IMB were in-
vestigated in the literature cited. Section 5 systemizes the available examples in
the frame of the methodology proposed by this review.