Kinetics and Thermodynamics of 1-anilino-8-naphthalene Sulfonate Interactions with Urinary Trypsin Inhibitor.

Zuo, Zhenyu; Fan, Handong; Guo, Jianjun; Zhou, Wei; Li, Lingling

The interactions between Urinary Trypsin Inhibitor (UTI) and 1-anilino-8-naphthalene sulfonate (ANS) were investigated by fluorescence spectra, isothermal titration calorimetry and molecular modeling. The results revealed the presence of four specific binding sites for ANS on UTI, with interactions driven mainly by electrostatic forces. The four specific binding sites indicated the involvement of four hydrophobic patches on UTI. Experimental data also confirmed the presence of a further five nonspecific binding sites that interacted mainly by the formation of salt bridges between the sulfonates of ANS and positive residues on the surface of UTI.

THERMODYNAMICS; URINARY trypsin inhibitor; NAPHTHALENE; SULFONATES; CHEMICAL kinetics; PROTEIN-protein interactions; FLUORESCENCE spectroscopy; ISOTHERMAL titration calorimetry

Protein Journal, 2012, Vol 31, Issue 7, p585

1572-3887

Academic Journal

10.1007/s10930-012-9443-4