In vitro and in silico investigations of the binding interactions between chlorophenols and trypsin.

Being the first-degree toxic pollutants, chlorophenols (CP) have potential carcinogenic and mutagenic activity and toxicity. Since there still lacks studies on molecular interactions of chlorophenols with trypsin, one major binding target of many exogenous environmental pollutants, the binding interactions between five chlorophenols, 2-CP, 2,6-DCP, 2,4,6-TCP, 2,4,6-TCP, 2,3,4,6-TCP and PCP and trypsin were characterized by the combination of multispectroscopic techniques and molecular modeling. The chlorophenols bind at the one main site of trypsin and the binding induces the changes of microenvironment and global conformations of trypsin.

Investigation of the interaction between chlorophenols and lysozyme in solution.

The binding interactions of lysozyme with 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol were investigated by UV-vis absorption, CD, fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. The binding constants, quenching mechanism, and the number of binding sites were determined by the quenching of lysozyme fluorescence in presence of chlorophenols.

Fluorescence spectroscopic investigation of the interaction between triphenyltin and humic acids.

The interaction between triphenyltin (TPT) and humic acid (HA) was investigated using UV-vis and fluorescence spectra techniques. The experimental results showed that the fluorescence quenching of HA by TPT was a result of the interaction of TPT with HA. The binding constant K(b) and corresponding thermodynamic parameters were measured at different temperatures.

Binding of Al(III)-tetracarboxyphthalocyanine to hemoglobin and myoglobin.

The interactions between Al(III)-tetracarboxyphthalocyanine (AlPc(COOH)(4)) and hemoglobin (or myoglobin) have been studied. The results showed that AlPc(COOH)(4) effectively quenched the intrinsic fluorescence of Hb and Mb via static quenching. The hydrophobic and electrostatic interactions played a major role in stabilizing the AlPc(COOH)(4)-protein complex.

Studies on the interactions of 2, 4-dinitrophenol and 2, 4-dichlorphenol with trypsin.

The interactions of 2, 4-dinitrophenol and 2, 4-dichlorphenol with trypsin were investigated by fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. The 2, 4-dinitrophenol and 2, 4-dichlorphenol effectively quenched the intrinsic fluorescence of trypsin via static quenching.

Investigation of the interactions of quercetin and morin with trypsin.

The interactions of quercetin and morin with trypsin were investigated by UV-vis absorption, fluorescence, synchronous fluorescence and three-dimensional fluorescence spectra techniques under physiological pH 7.40. Quercetin and morin effectively quenched the intrinsic fluorescence of trypsin via static quenching.

Studies on the interaction between imidacloprid and human serum albumin: spectroscopic approach.

The interaction between imidacloprid (IMI) and human serum albumin (HSA) was investigated using fluorescence and UV/vis absorption spectroscopy. The experimental results showed that the fluorescence quenching of HSA by IMI was a result of the formation of IMI-HSA complex; static quenching was confirmed to result in the fluorescence quenching. The apparent binding constant K(A) between IMI and HSA at three differences were obtained to be 1.

Studies on the interaction of caffeine with bovine hemoglobin.

Caffeine (CF) is a member of the methylxanthine family with numerous biological activities, which may contribute to the prevention of human disease but also may be potentially harmful. In the present study, the interaction of CF with bovine hemoglobin (BHb) under physiological condition was studied by fluorescence and UV/vis spectroscopy. Fluorescence data revealed that the fluorescence quenching of BHb by CF was the result of the formed complex of CF-BHb.

Studies of the interaction between paraquat and bovine hemoglobin.

The interaction between paraquat (PQ) and bovine hemoglobin (BHb) was investigated using fluorescence and UV/vis absorption spectroscopy. The reactivity of the heme centers with superoxide anions formed by PQ was judged on the basis of the decrease of the Soret band. The experimental results showed that the fluorescence quenching of BHb by PQ was a result of the formation of PQ-BHb complex; static quenching was confirmed to result in the fluorescence quenching.