Fluorimetric study of interaction of merbromin with trypsin.

Debashis Banerjee, Parimal Kumar Das, Haraprasad Singha, Sanjib Bagchi

Index: Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 70(5) , 1109-13, (2008)

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Abstract

Interaction of merbromin with trypsin is of bovine origin has been studied by monitoring the absorption steady-state and time-resolved fluorescence spectral properties of the dye. Studies have been done in media of varying pH at different trypsin concentrations. It has been observed that trypsin brings about a quenching of fluorescence of the dye. The quenching is static in nature and the equilibrium constant of dye-trypsin interaction in the ground-state has been determined from quenching studies. Steady-state anisotropy of the dye increases in presence of trypsin in the medium. Values of micro-viscosity in the vicinity of the fluorophore in media containing trypsin have been determined from measurements of fluorescence anisotropy. Time-resolved fluorescence studies indicate the existence of two decaying states for the dye. The fractional contribution to the time-resolved decay changes with pH. The average lifetime, however, does not depend on the concentration of trypsin.