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Updated: May 3, 2026

Measuring Enzymatic Stability by Isothermal Titration Calorimetry

Measuring Enzymatic Stability by Isothermal Titration Calorimetry

Published on: March 26, 2019

Observing single enzyme molecules interconvert between activity states upon heating.

Marcin J Rojek¹, David R Walt¹

¹Department of Chemistry, Tufts University, Medford, Massachusetts, United States of America.

|January 28, 2014

Summary

This summary is machine-generated.

Single enzyme molecules of beta-galactosidase switch between activity states when heated. These changes are due to different enzyme conformations, revealing insights into enzyme heterogeneity.

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Measuring Enzymatic Stability by Isothermal Titration Calorimetry

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Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions

Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions

Published on: April 4, 2014

Area of Science:

Biochemistry
Enzymology
Single-molecule biophysics

Background:

Enzyme activity heterogeneity is a known phenomenon.
Understanding the origins of this heterogeneity is crucial for enzyme function studies.

Purpose of the Study:

To investigate the dynamic behavior of single beta-galactosidase enzyme molecules.
To determine if external stimuli, like heat, can alter enzyme activity states.
To link observed activity changes to specific enzyme conformations.

Main Methods:

Trapping hundreds of single beta-galactosidase molecules in femtoliter reaction chambers.
Subjecting individual enzymes to short, controlled heating pulses.
Monitoring individual enzyme activity states in real-time.

Main Results:

Single beta-galactosidase molecules interconvert between different activity states upon heat exposure.
Activity state changes are random and independent of the enzyme's initial activity.
These dynamic changes are attributed to distinct, stable enzyme conformations.

Conclusions:

Heat-induced conformational changes drive dynamic alterations in enzyme activity.
Stable enzyme conformations contribute significantly to observed population heterogeneity.
This study provides a molecular-level understanding of enzyme static heterogeneity.