N-乙酰-L-酪氨酸酰胺的三光子激发

Three-photon excitation of N-acetyl-L-tyrosinamide.

作者信息

Gryczynski I, Malak H, Lakowicz J R

机构信息

Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore 21201, USA.

出版信息

Biophys Chem. 1999 May 17;79(1):25-32. doi: 10.1016/s0301-4622(99)00033-2.

DOI:10.1016/s0301-4622(99)00033-2

PMID:10371019

Abstract

We observed emission from the tyrosine derivative N-acetyl-L-tyrosinamide (NATyrA) when excited with the fundamental output of a femtosecond Ti:Sapphire laser from 780 to 855 nm. The dependence on incident laser power indicates a three-photon process. The emission spectra and intensity decay in glycerol-water (30:70) at 5 degrees C were found to be identical for one- and three-photon excitation. Also the excitation spectrum of three-photon-induced fluorescence of NATyrA corresponds to the one-photon excitation spectrum. The time-zero or fundamental anisotropy spectrum was reconstructed from the frequency-domain anisotropy decays. The three-photon anisotropies are similar or larger than the one-photon anisotropies. These three-photon anisotropies are surprising given the near zero values known for tyrosine with two-photon excitation. The observations indicate that one- and three-photon excitation directly populates the same singlet excited states(s). However, the origin of the anisotropies with multi-photon excitation of tyrosine remain unclear and unpredictable.

摘要

当用飞秒钛宝石激光器从780至855nm的基频输出进行激发时，我们观察到了酪氨酸衍生物N - 乙酰 - L - 酪氨酸酰胺（NATyrA）的发射。对入射激光功率的依赖性表明这是一个三光子过程。发现在5摄氏度下甘油 - 水（30:70）中，单光子和三光子激发的发射光谱以及强度衰减是相同的。此外，NATyrA的三光子诱导荧光的激发光谱与单光子激发光谱相对应。通过频域各向异性衰减重建了零时刻或基态各向异性光谱。三光子各向异性与单光子各向异性相似或更大。考虑到酪氨酸双光子激发时已知的接近零的值，这些三光子各向异性令人惊讶。这些观察结果表明，单光子和三光子激发直接填充到相同的单重激发态。然而，酪氨酸多光子激发的各向异性的起源仍不清楚且无法预测。