School of Automation and Electrical Engineering, University of Science and Technology Beijing, Beijing, China; Institute of Laser Engineering, Osaka University, Suita, Osaka, Japan.
Institute of Laser Engineering, Osaka University, Suita, Osaka, Japan.
Biophys J. 2020 Dec 15;119(12):2469-2482. doi: 10.1016/j.bpj.2020.11.003. Epub 2020 Nov 13.
Terahertz waves have attracted great attention in biomolecule research because of the fact that they cover the range of energy levels of weak interactions, skeleton vibrations, and dipole rotations during inter- and intramolecular interactions in biomacromolecules. In this study, we validated the feasibility of employing terahertz time-domain spectroscopy (THz-TDS) for the nondestructive and label-free monitoring of protein digestion. The acid protease, pepsin, was used at its optimal pH to hydrolyze bovine serum albumin. Correspondingly, the control group experiment was also conducted by adjusting the pH value to inactivate pepsin. The progress of these two experiments was tracked by a compact commercial THz-TDS for 1 h. On one hand, the reaction-time-dependent absorption coefficient was calculated, and a direct absorption coefficient analysis was completed. The results indicate that protein hydrolysis can be easily monitored over time by focusing on the variation tendency of the absorption coefficient from a macroscopic perspective. On the other hand, we explored the use of the Debye model to analyze the dielectric properties of the solution during protein hydrolysis. The results of the Debye analysis prove that it is possible to investigate in detail the microscopic dynamics of biomacromolecule solutions at the molecular level by THz-TDS. Our research examined the process of protein hydrolysis by a combination of absorption spectra and Debye analysis and demonstrated that terahertz spectroscopy is a powerful technology for the investigation of biomolecular reactions, with potential applications in variety of fields.
太赫兹波在生物分子研究中引起了极大的关注，因为它们覆盖了生物大分子中分子间和分子内相互作用过程中弱相互作用、骨架振动和偶极旋转的能级范围。在这项研究中，我们验证了太赫兹时域光谱（THz-TDS）用于无损和无标记监测蛋白质消化的可行性。使用酸性蛋白酶胃蛋白酶在其最佳 pH 值下水解牛血清白蛋白。相应地，还通过调节 pH 值使胃蛋白酶失活来进行对照组实验。使用紧凑型商业太赫兹时域光谱仪在 1 小时内跟踪这两个实验的进展。一方面，计算了随时间变化的吸收系数，并完成了直接吸收系数分析。结果表明，通过从宏观角度关注吸收系数的变化趋势，可以轻松监测蛋白质水解过程随时间的变化。另一方面，我们探索了使用 Debye 模型分析蛋白质水解过程中溶液的介电特性。Debye 分析的结果证明，通过太赫兹时域光谱仪可以在分子水平上详细研究生物大分子溶液的微观动力学。我们的研究通过吸收光谱和 Debye 分析相结合来检查蛋白质水解的过程，并证明太赫兹光谱是研究生物分子反应的强大技术，具有广泛的应用领域。
