Heat Denaturation of Proteins by DSC

Significance of the topic

Protein stability and function depend on higher-order structures affected by solvent, temperature, and pH. Evaluating protein stability via DSC is critical for formulation and processing in biotechnology and pharmaceuticals.

Objectives and overview

This study employed DSC-60 Plus to determine thermal denaturation temperatures of egg white-derived protein and lysozyme under various conditions, including concentration and pH.

Instrumentation used

Shimadzu DSC-60 Plus differential scanning calorimeter with sealed aluminum sample cells was utilized for all measurements.

Methodology

Egg white protein (10.4%) and lysozyme (0.2% and 2.5%) were prepared in 0.2 M phosphate buffer at pH 7.05. Samples were heated from 40 °C to 100 °C at a rate of 5 °C/min. Additional lysozyme samples (10%) were prepared at pH 4.20, 7.05, and 9.10 to assess pH dependence.

Main results and discussion

Egg white-derived protein exhibited an endothermic peak at 83.5 °C. Lysozyme denaturation peaks were observed at 74.9 °C (2.5%) and 75.1 °C (0.2%), demonstrating high sensitivity even at low concentration. pH variation influenced stability: denaturation temperature increased from 72.0 °C at pH 9.10 to 77.4 °C at pH 4.20, indicating enhanced stability under acidic conditions.

Benefits and practical applications

• High baseline stability of DSC-60 Plus allows accurate detection at low protein concentrations.
• DSC profiles support formulation optimization in protein therapeutics and quality control processes.
• pH-dependent stability insights guide buffer selection in research and industrial workflows.

Future trends and potential applications

Advances may include high-throughput DSC screening, integration with computational modeling for predictive stability, development of portable calorimeters for process monitoring, and application to complex or multi-component protein systems.

Conclusion

The Shimadzu DSC-60 Plus provides reliable and sensitive measurement of protein thermal stability across various concentrations and pH conditions. Its use enhances research and industrial analysis of protein formulations.

Reference

Shimadzu Application Note T150. Heat Denaturation of Proteins by DSC. First Edition: May 2015.