【摘要】 利用太赫兹时域光谱研究了三种芳香族氨基酸,即酪氨酸、色氨酸和苯丙氨酸,在0.2—1.6THz波段的光学特性,得到了对应的吸收谱.对比各自的吸收谱发现,酪氨酸和色氨酸分别在0.976THz和1.465THz有明显的吸收峰,而苯丙氨酸则没有明显的吸收峰.利用密度泛函(DFT)理论初步计算表明,氨基酸在THz波段的吸收是由分子转动或扭动造成的,氨基酸的不同结构造成了它们在THz波段不同的吸收峰位.另外,还得到了三种氨基酸在该波段的折射率谱并首次定量给出了三种氨基酸在0.2—1.6THz波段的平均折射率.酪氨酸、色氨酸和苯丙氨酸的平均折射率分别为1.507,1.526和1.686.这项研究不仅为研究生物分子结构和动力学提供了新的理论和实验方法,而且对进一步利用THz时域光谱研究其他生物大分子具有借鉴意义.更多还原

【Abstract】 We have studied the optical properties of three kinds of aromatic amino acids including tyrosine, tryptophane and phenylalanine using THz time domain spectroscopy between 0.2 and 1.6 THz.Comparing their absorption spectra,we find that tyrosine and tryptophane have sharp absorption peaks at 0.976THz and 1.465THz respectively,while phenylalanine does not have absorption peak in this range.This result shows the capability of THz time domain spectroscopy to distinguish different molecules.Calculating by density functional,we found that the absorption peaks are caused by the rotation and torsion of the molecules.The average refractive indexes of these three amino acids are also obtained:they are 1.507,1.526 and 1.686 respectively.This work not only is significant for the research of molecular structure and molecular dynamics,but can also provide reference for studying other large biological molecules by THz time domain spectroscopy.更多还原