title: A study of the interaction between malachite green and lysozyme by steady-state fluorescence.
abstract: The interaction of a N-methylated diaminotriphenylmethane dye, malachite green, with lysozyme was investigated by fluorescence spectroscopic techniques under physiological conditions. The binding parameters have been evaluated by fluorescence quenching methods. The results revealed that malachite green caused the fluorescence quenching of lysozyme through a static quenching procedure. The thermodynamic parameters like DeltaH and DeltaS were calculated to be -15.33 kJ mol(-1) and 19.47 J mol(-1) K(-1) according to van't Hoff equation, respectively, which proves main interaction between malachite green and lysozyme is hydrophobic forces and hydrogen bond contact. The distance r between donor (lysozyme) and acceptor (malachite green) was obtained to be 3.82 nm according to Frster's theory. The results of synchronous fluorescence, UV/vis and three-dimensional fluorescence spectra showed that binding of malachite green with lysozyme can induce conformational changes in lysozyme. In addition, the effects of common ions on the constants of lysozyme-malachite green complex were also discussed.
authors.affiliation: Department of Chemistry, China Agricultural University, 2 Yuan-ming-yuan xi Road, Haidian District, Beijing 100193, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Ding
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun