在不同激发波长下的单壁碳纳米管的拉曼光谱研究

采用直流电弧法制备单壁碳纳米管样品,用457.5和632.8nm两种不同的激发光分别测得单壁碳纳米管的正常拉曼光谱和共振拉曼光谱.通过理论分析得到了单壁碳纳米管的直径分布,进一步推测了其类型及结构参数;对单壁碳纳米管的正切拉伸模的成分进行了归属.在632.8nm激发波长下得到了IG/ID值随激光功率变化的曲线,认为在2.5mW时,单壁碳纳米管缺陷的结构可能发生了改变.在用457.5nm波长激发的单壁碳纳米管的拉曼光谱中,首次发现了1421cm-1的拉曼谱峰.

Studies on Tryptophan Residue Modification and Fluorescence Spectrum of Hyaluronidase

Tryptophan residues in Hyaluronidase(HAase) were modified by N-bromosuccinimide(NBS). The results indicated that there were eleven tryptophan residues in HAase and one of them was exposed, which was proved to be essential for the activity of the enzyme. The study on fluorescence quenching of HAase showed that KI could not quench all of the fluorescence from Trp residues in HAase . Acrylamide(Acr), a polarized quencher without electronic charge, could quench almost all of the fluorescence from Trp residues in HAase . The collisional quenching constants(K-D) of HAase at different concentrations of Acr were calculated in terms of Stern-Volmer equation. The results implied that some of Trp residues were buried in the interior of HAase, and the Trp residue on the surface of HAase was not located in the hydrophobic pocket.