Fast scanning calorimetry of lysozyme unfolding at scanning rates from 5 K/min to 500,000 K/min

• Published in: Biochimica et biophysica acta. General subjects Vol. 1862; no. 9; pp. 2024 - 2030
• Main Authors: Mukhametzyanov, Timur A., Sedov, Igor A., Solomonov, Boris N., Schick, Christoph
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2018
• Subjects: Animals; calorimeters; Calorimetry, Differential Scanning - instrumentation; Calorimetry, Differential Scanning - methods; Denaturation; differential scanning calorimetry; evaporation; Fast scanning calorimetry; glycerol; Lysozyme; Muramidase - chemistry; Protein; Protein Denaturation; Protein Folding; proteins; solvents; spray drying; surface area; temperature; Thermal stability; Fast scanning calorimetry; Denaturation; Protein; Lysozyme; Thermal stability
• ISSN: 0304-4165; 1872-8006
• DOI: 10.1016/j.bbagen.2018.06.019

Protein denaturation is often studied using differential scanning calorimetry (DSC). However, conventional instruments are limited in the temperature scanning rate available. Fast scanning calorimetry (FSC) provides an ability to study processes at much higher rates while using extremely small sample masses [ng]. This makes it a very interesting technique for protein investigation. A combination of conventional DSC and fast scanning calorimeters was used to study denaturation of lysozyme dissolved in glycerol. Glycerol was chosen as a solvent to prevent evaporation from the micro-sized samples of the fast scanning calorimeter. The lysozyme denaturation temperatures in the range of scanning rates from 5 K/min to ca. 500,000 K/min follow the Arrhenius law. The experimental results for FSC and conventional DSC fall into two distinct clusters in a Kissinger plot, which are well approximated by two parallel straight lines. The transition temperatures for the unfolding process measured on fast scanning calorimetry sensor are significantly lower than what could be expected from the results of conventional DSC using extrapolation to high scanning rates. Evidence for the influence of the relative surface area on the unfolding temperature was found. For the first time, fast scanning calorimetry was employed to study protein denaturation with a range of temperature scanning rates of 5 orders of magnitude. Decreased thermal stability of the micro-sized samples on the fast scanning calorimeter raise caution over using bulk solution thermal stability data of proteins for applications where micro-sized dispersed protein solutions are used, e.g., spray drying. •Denaturation of lysozyme in glycerol was studied using fast scanning calorimetry.•Scan rates from 0.08 K/s to 8000 K/s were used.•Denaturation follows Arrhenius behavior in the entire range of scanning rates.•Thermal stability of lysozyme on the chip-sensor is diminished.