Studies on the interaction between benzidine and hemocyanin from Chinese mitten crab Eriocheir japonica sinensis (Decapoda, Grapsidae)

The interaction of benzidine (BZ) with hemocyanin (Hc) from Chinese mitten crab (Eriocheir japonica sinensis) was studied by fluorescence spectrum. BZ can quench the fluorescence of Hc by forming a new complex. The process of binding BZ on Hc was a spontaneous molecular interaction procedure. The thermodynamic parameters, the enthalpy change and entropy change were estimated to be 47.36 kJ mol−1, 248.51 J mol−1 K−1 according to the van' Hoff equation. This indicates that hydrophobic interaction played a major role in stabilizing the complex. The results of synchronous fluorescence spectroscopy and three-dimensional fluorescence spectra indicated that the structure of these tyrosine residues environments was altered by BZ, which could enter into the hydrophobic pocked of Hc.