Time

Figure 8.9 Predicted models showing various electropherograms in a capillary electro-phoretic enzyme assay. The moving velocities are ESP (A) and PES (fl); (C) multiple-isoenzyme form, with the moving velocity of the common product smaller than those of these isoenzymes. (From Bao and Regnier, 1992, with permission.)

material as possible, undiluted fermentation broth was injected directly into the capillary. Also, the volume of the injected sample was as much as 30 nL, which, on the other hand, decreases separation efficiency. For separation, 33 mM phosphate buffer (pH 9.5) was used, and the separation was carried out at 15 kV.

Finally, if the product of the enzymatic reaction is known, the activity of the enzyme can be assayed on the basis of quantitating the product "off line." Thus, for instance, glutathione peroxidase activity can be measured by quantitating the oxidized and reduced forms of glutathione by capillary electrophoresis, as demonstrated by Pascual et al. (1992). The electropho-retic separation buffer used was 100 mM tetraborate (pH 8.2), containing 100 mM SDS.

Figure 8.10 Electropherograms showing accumulated peaks resulting from the parked reaction at different running times, (/t) NADPH accumulated at the beginning before electrophoresis. (B) NADPH accumulated just before glucose-6-phosphate oxidore-ductase passed the detection window. (From Bao and Regnier 1992, with permission.)

Figure 8.10 Electropherograms showing accumulated peaks resulting from the parked reaction at different running times, (/t) NADPH accumulated at the beginning before electrophoresis. (B) NADPH accumulated just before glucose-6-phosphate oxidore-ductase passed the detection window. (From Bao and Regnier 1992, with permission.)

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