Solvation dynamics in the denatured state of a protein, lysozyme (denatured by sodium dodecyl sulfate, SDS) is markedly slower than that in the native state. For coumarin 153 bound to lysozyme, the average solvation time, is 330 ps. In the lysozyme-SDS complex, the solvation dynamics is markedly slower with = 7250 ps. On addition of dithiothreitol (DTT) to the lysozyme-SDS complex, when the di-sulfide bonds are destroyed, is found to be 1140 ps. The slow dynamics in the denatured protein is attributed to the polymer chain dynamics and the exchange of bound and free water molecules. (C) 2003 Elsevier B.V. All rights reserved.