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

Petersen SB, Fojan P, Petersen EI, Petersen MT - J. Biomed. Biotechnol. (2001)

Bottom Line: The ratio between the calorimetric enthalpy (DeltaH(cal)) and the van't Hoff enthalpy (DeltaH(v)) 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.

View Article: PubMed Central - HTML - PubMed

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 (DeltaH(cal)) and the van't Hoff enthalpy (DeltaH(v)) 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.

No MeSH data available.


Related in: MedlinePlus

Scanrate dependence of Tm at different pH values. Scanrate dependence of cutinase at pH 4.00, 6.00, and 8.5. The scans were performed in three different buffers. The scanrates varied from 90 to 10°C/h. From the dependence of Tm on the scanrate the rate constant for the unfolding can be determined.
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Figure 3: Scanrate dependence of Tm at different pH values. Scanrate dependence of cutinase at pH 4.00, 6.00, and 8.5. The scans were performed in three different buffers. The scanrates varied from 90 to 10°C/h. From the dependence of Tm on the scanrate the rate constant for the unfolding can be determined.

Mentions: The influence of the scanrate on the apparent Tm at pH 4.0, 6.0, and 8.5 was also investigated (Figure 3). As is seen from Figure 3, the higher the scanrate, the higher the apparent Tm. However, the shift of Tm observed over the scanrates applied in the present study (10°C/h to 90°C/h) varied from 3°C at pH 8.5 to about 1°C at pH 6.0. When plotting the peak half width (T1/2) of the calorimetric transitions observed against pH (Figure 4) a minimum is displayed at around pH 6.0 where the least variation in scanrate dependence has been observed.


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

Petersen SB, Fojan P, Petersen EI, Petersen MT - J. Biomed. Biotechnol. (2001)

Scanrate dependence of Tm at different pH values. Scanrate dependence of cutinase at pH 4.00, 6.00, and 8.5. The scans were performed in three different buffers. The scanrates varied from 90 to 10°C/h. From the dependence of Tm on the scanrate the rate constant for the unfolding can be determined.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC113781&req=5

Figure 3: Scanrate dependence of Tm at different pH values. Scanrate dependence of cutinase at pH 4.00, 6.00, and 8.5. The scans were performed in three different buffers. The scanrates varied from 90 to 10°C/h. From the dependence of Tm on the scanrate the rate constant for the unfolding can be determined.
Mentions: The influence of the scanrate on the apparent Tm at pH 4.0, 6.0, and 8.5 was also investigated (Figure 3). As is seen from Figure 3, the higher the scanrate, the higher the apparent Tm. However, the shift of Tm observed over the scanrates applied in the present study (10°C/h to 90°C/h) varied from 3°C at pH 8.5 to about 1°C at pH 6.0. When plotting the peak half width (T1/2) of the calorimetric transitions observed against pH (Figure 4) a minimum is displayed at around pH 6.0 where the least variation in scanrate dependence has been observed.

Bottom Line: The ratio between the calorimetric enthalpy (DeltaH(cal)) and the van't Hoff enthalpy (DeltaH(v)) 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.

View Article: PubMed Central - HTML - PubMed

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 (DeltaH(cal)) and the van't Hoff enthalpy (DeltaH(v)) 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.

No MeSH data available.


Related in: MedlinePlus