The decreased enzyme activity of trypsin resulted from its conformation changes in presence of triclocarban.

Abstract

Triclocarban (TCC), a widely used antimicrobial agent, may threaten ecosystems and human health via bioaccumulation, necessitating study of its protein interactions to understand molecular toxicity. In this paper, trypsin (TRY) was utilized as a model protein to explore its binding to TRY. The results revealed that the binding could result in a reduction of the enzymatic activity of TRY. Spectra analysis showed that TCC could heighten the quenching effect on the intrinsic fluorescence of TRY. The fluorescence quenching of TRY encompassed dynamic and static quenching mechanisms. The association constants (K_a) exhibited a high magnitude (∼10⁶) at both 293 and 313 K, indicating a robust affinity between the two entities. Molecular docking studies and thermodynamic parameters (ΔH < 0, ΔS < 0) suggested hydrogen bonds and van der Waals forces are necessary for TCC's binding to TRY. The formation of the TRY-TCC complex induced alterations in the secondary structure and local microenvironment of TRY, leading to a more relaxed skeletal structure. This paper will provide a fundamental basis for further studying the molecular toxicity of TCC in living organisms. Future in vivo studies will be essential to establish the physiological consequences of TCC-TRY binding in biological systems.