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Journal of Biomedicine and Biotechnology
Volume 1 (2001), Issue 2, Pages 62-69
http://dx.doi.org/10.1155/S1110724301000249
Research article

The Thermal Stability of the Fusarium solani pisi Cutinase as a Function of pH

Institute of Life Science, Sohngaardsholmsvej 49, Aalborg Dk-9000, Denmark

Copyright © 2001 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We have investigated the thermal stability of the Fusarium solani pisi cutinase as a function of pH, in the range from pH 2–12. Its highest enzymatic activity coincides with the pH-range at which it displays its highest thermal stability. The unfolding of the enzyme as a function of pH was investigated by microcalorimetry. The ratio between the calorimetric enthalpy (ΔHcal) and the van′t Hoff enthalpy (ΔHv) obtained, is far from unity, indicating that cutinase does not exhibit a simple two state unfolding behaviour. The role of pH on the electrostatic contribution to the thermal stability was assessed using TITRA. We propose a molecular interpretation for the pH-variation in enzymatic activity.