Journal of Physical Chemistry p. 5713 - 5723 (1995)
Update date:2022-08-29
Topics:
Eftink, Maurice R.
Jia, Yiwei
Hu, Dana
Ghiron, Camillo, A.
The fluorescence of a large set of tryptophan analogues, including several that are conformationally constrained, was studied.The constrained analogues include tetrahydrocarboline-3-carboxylic acid and 3-amino-3-carboxytetrahydrocarbazole.Steady state and time-resolved fluorescence measurements were made as a function of pH.The fluorescence quantum yields of the constrained analogues are higher than those for the unconstrained counterparts.The emission intensity of the constrained analogues, as well as 4-methyltryptophan, decreases with deprotonation of the side chain α-ammonium groups; this is in contrast to the increase in fluorescence of tryptophan with deprotonation of this group.These results are consistent with the existence of excited state proton transfer to carbon 4 of the indole ring as a quenching mechanism, which is sterically prohibited in the constrained analogues and 4-methyltryptophan.From quantum yield and lifetime data (most decays are nonexponential), the effective rate constant for nonradiative depopulation of the excited state was calculated.For tryptophan analogues having two side chain functional groups, there is a synergistic effect; the presence of two side chain groups causes more quenching than expected from the sum of the individual contributions.For analogues having an α-ammonium group, this synergism appears to be correlated with an induced change in the pKa of this group.Deprotonation of this α-ammonium group also caused a red shift in the emission of these compounds; this appears to be due to electrostatic repulsion between the α-NH3+ group and the excited indole dipole.
View MoreShanghai Pengkai Chemical Co.,Ltd
Contact:+86-21-60526671
Address:No.4226 Duzhuang Rd Minhang District Shanghai China
shijiazhuang shuanglian chemical industry co.,ltd
Contact:0311-82190302
Address:Luquan Intersection , Shijiazhuang--Taiyuan Expressway,Shijiazhuang City
Changde Yungang Biotechnology Co., Ltd
website:http://www.cdyg.com
Contact:+86-736-7391178
Address:Qiaonan Industrial Park, Changde City, Hunan Province
Henan Yellow River New Material Technology Co.Ltd.
website:http://www.yellowriverchem.com
Contact:0086-373-7278760
Address:Chengguan Town, Yuanyang County
Hangzhou Pharma & Chem Co.,Ltd.
Contact:+86-571-87040515
Address:No,139Qingchun Rd
Doi:10.1021/acs.langmuir.0c03609
(2021)Doi:10.1021/ja01862a085
(1940)Doi:10.1002/anie.201608116
(2016)Doi:10.1039/J29700001733
(1970)Doi:10.1021/om500707e
(2014)Doi:10.1246/cl.1983.325
(1983)