This page summarizes the optical absorption and emission data of Tryptophan that is available in the PhotochemCAD package, version 2.1a (Du 1998, Dixon 2005). I reworked their data to produce these interactive graphs and to provide direct links to text files containing the raw and manipulated data. Although I have tried to be careful, I may have introduced some errors; the cautious user is advised to compare these results with the original sources.
This optical absorption measurement of Tryptophan were made by R.-C. A. Fuh in the summer of 1995 using a Cary 3. The absorption values were collected using a spectral bandwidth of 1.0 nm, a signal averaging time of 0.133 sec, a data interval of 0.25 nm, and a scan rate of 112.5 nm/min.
These measurements were scaled to make the molar extinction coefficient match the value of 5,579cm-1/M at 278.0nm (Fasman, 1976).
The fluorescence emission spectrum of Tryptophan dissolved in water, 0.1 M phosphate buffer, pH 7. The excitation wavelength was 270nm. The quantum yield of this molecule is 0.12 (Chen, 1972). This spectrum was collected by in the summer of 1995 using a Spex FluoroMax. The excitation and emission monochromators were set at 1 mm, giving a spectral bandwidth of 4.25 nm. The data interval was 0.5 nm and the integration time was 2.0 sec.
Samples were prepared in 1cm pathlength quartz cells with absorbance less than 0.1 at the excitation and all emission wavelengths to uniformly illuminate across the sample, and to avoid the inner-filter effect. The dark counts were subtracted and the spectra were corrected for wavelength-dependent instrument sensitivity.
Chen, R. F. (1972) Measurements of absolute values in biochemical fluorescence spectroscopy. J. Research National Bureau Standards 76A(6), 593-606. The same article appeared in Accuracy in Spectrophotometry and Luminescence Measurements, Nat. Bureau of Standards Special Publication 378, 183-196 (1973).
Dixon, J. M., M. Taniguchi and J. S. Lindsey (2005), "PhotochemCAD 2. A Refined Program with Accompanying Spectral Databases for Photochemical Calculations, Photochem. Photobiol., 81, 212-213.
Du, H., R.-C. A. Fuh, J. Li, L. A. Corkan and J. S. Lindsey (1998) PhotochemCAD: A computer-aided design and research tool in photochemistry. Photochem. Photobiol. 68, 141-142.
Eaton, D. F. (1988) Reference materials for fluorescence measurement. Pure Appl. Chem. 60, 1107-1114.
Fasman, G. D., Editor (1976) Handbook of Biochemistry and Molecular Biology, 3rd Edition, Proteins, Volume I, pp. 183-203, CRC Press, Cleveland, Ohio.
Kirby, E. P. and R. F. Steiner (1970) The influence of solvent and temperature upon the fluorescence of indole derivatives. J. Phys. Chem. 74, 4480-4490.
© 5 March 2012 Scott Prahl