Static and Dynamic Quenching of Tryptophan Fluorescence in Various Proteins by a Chromium (III) Complex |
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Authors: | Heather F Crouse Elyse M Petrunak Ashley M Donovan Anna C Merkle Brandi L Swartz |
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Institution: | 1. Department of Chemistry , Susquehanna University , PA, U.S.A.;2. Department of Chemistry , Bryn Mawr College , Bryn Mawr, PA, U.S.A. |
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Abstract: | The interaction of a chromium (III) complex, (R,R)-N,N′-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-diaminochromium (III), with human serum albumin, bovine serum albumin, lysozyme, and free tryptophan was studied using steady-state fluorescence spectroscopy. Dynamic and static quenching constants were calculated using Stern-Volmer kinetics. The complex bound more tightly to the serum albumins than to lysozyme or free tryptophan, but only one binding site was determined in all systems. The interaction was also determined to be thermodynamically favorable, and the binding constants were on the order of 103–106. The fluorescence quenching was static in nature with Forster distances in the 1.8–2.0 nm range. |
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Keywords: | Cr (III) complex fluorescence static and dynamic quenching Stern-Volmer tryptophan |
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