ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Monitoring of Soluble Enzyme Activity by Enzyme Flow Microcalorimetry

V. Štefuca and M. Polakovič

Department of Chemical and Biochemical Engineering, Faculty of Chemical Technology, Slovak University of Technology, SK-812 37 Bratislava

E-mail: stefuca@cvt.stuba.sk

Abstract: The possibility of use of the flow microcalorimetry for the enzyme activity testing is demonstrated. Two model enzymes, urease and invertase, were studied, when urea and sucrose were used as substrates. The technique is based on a measurement of temperature change in the sample stream provoked by the reaction heat effect of enzyme reaction. The analysis is conducted so that a pre-cooled sample of enzyme solution is mixed with the substrate solution, and then immediately injected through an injection valve into a carrier buffer pumped continuously into the flow microcalorimeter column packed with glass particles. A temperature change in the column is observed as a heat peak while the peak area depends on the sample volume and an enzymatic reaction rate.The enzyme activity in the sample was determined from the peak height using a previous microcalorimeter calibration for the known enzyme activity. The set of calibrations was effectuated for both tested enzymes. Enzyme activity ranges of linearity and the influence of substrate concentration on the method sensitivity were investigated. The main advantage of the proposed technique is its versatility due to the versatility of the detection principle.

Full paper in Portable Document Format: 536a362.pdf

Chemical Papers 53 (6) 362–365 (1999)