Study On The Interactions Of Biomacromolecules And Lean Meat Powder Drug

In recently years, food safety has become a hot issue for the whole society. With the development of new medium, the incidents of food safety have been frequently exposed, such as: melamine events, lean meat powder events, gutter oil events, et al. They are severe threat to human security. The lean meat powder is a kind of β-agonist steroid, it can promote the growth of lean meat, accelerate the transformation and decomposition of fat. It is great harmful for human when the lean meat powder was ingested to human body. Therefore, the exploration of interaction between lean meat powder and biomolecule can provide important basis for transmission, anabolism and toxicological mechanism in the body at molecular level, and provide useful information for food safety.In this assay, five kinds of lean meat powder binding to DNA and serum albumin in vitro were explored by spectroscopic experiment, as well as viscometry and molecule docking techniques. The main points are below:The salmeterol xinafoate(SX) binding to calf thymus DNA in vitro was explored by multi-spectroscopic methods. It was found that SX could bind to DNA, the quenching of fluorescence of SX by DNA was a static quenching, and the binding constants(Ka) were determined as 8.5 ′ 103, 8.3 ′ 103 and 6.1 ′ 103 L mol-1 at 18, 28 and 38 °C respectively. When bound to DNA, SX showed fluorescence quenching in the fluorescence spectra and hyperchromic effect in the absorption spectra. The relative viscosity and melting temperature of DNA solution were hardly influenced by SX, while the fluorescence intensity of SX-DNA was observed obviously decrease with the increasing ionic strength of system. Also, the binding constant of SX-ds DNA system was much higher than that of SX-ss DNA. All these results suggested that the binding mode of SX to DNA should be groove binding. Furthermore, electrostatic force might play a predominant role in SX binding to DNA. The quantum yield(φ) of SX was measured as 0.13 using comparing method. The binding distance(r0) between the SX and DNA was calculated as 4.10 nm.The interaction of terbutaline sulfate(TS) with ct DNA was investigated through fluorescence, UV-Vis absorption, viscosity measurements, ionic strength effect, DNA melting experiments and molecular docking. TS was found to bind to ct DNA, with binding constants of 4.92 × 104, 1.26 × 104 and 1.16 × 104 L mol-1 at 290, 300 and 310 K, respectively.. The binding mode of TS to ct DNA should be groove binding. The enthalpy change and entropy change suggested that van der Waals force or hydrogen bonds was a main binding force between TS and ct DNA. Molecular docking showed that TS was a minor groove binder of ct DNA and preferentially bound to A-T rich regions. Furthermore, the quantum yield of TS was measured by comparing with the standard solution. The binding distance between TS and ct DNA was 3.48 nm.The interactions of mapenterol with BSA and HSA have been investigated systematically by fluorescence, UV-vis absorption, circular dichroism(CD) and molecular docking techniques. The mechanism study suggested that mapenterol can quench the fluorescence of BSA and HSA through static quenching. At 291 K, the binding constants KA values were 1.93 ± 0.04 × 103 and 2.73 ± 0.02 × 103 L mol–1 for mapenterol-BSA complex and mapenterol-HSA complex, respectively. The thermodynamic parameters displayed that electrostatic force and hydrophobic played an important role in stabilizing the complex of mapenterol-BSA/HSA. It was found from competitive studies that mapenterol was binding at Sudlow sites I on both BSA and HSA, The effects of K+, Ca2+, Cu2+, Zn2+ and Fe3+ on the binding were studied at 291 K. Synchronous fluorescence and CD spectra showed that mapenterol changes the secondary structure of BSA/HSA. Furthermore, the molecular docking study also indicated that mapenterol could strongly bind to the site I(sub-domain IIA) of BSA/HSA. The distances r0 were calculated to be 3.18 and 2.75 nm for mapenterol-BSA and mapenterol-HSA, respectively.The interactions of HSA with bromchlorbuterol(BCB) and phenylethanolamine A(PEA) were investigated by fluorescence, CD and molecular docking techniques. The quenching mechanism study suggested that BCB and PEA can effectively quench the fluorescence of HSA. The effects of K+, Ca2+, Cu2+, Zn2+ and Fe3+ on the BCB/PEA-HSA binding were studied at 292 K. The competition binding of BCB/PEA with HSA was also discussed. The thermodynamic parameters showed that BCB/PEA bind to HSA via hydrophobic force. Synchronous fluorescence and CD spectra showed that the conformations of HSA were changed by BCB and PEA. The site marker competitive studies suggested that BCB/PEA was binding at Sudlow sites I on HSA. The study of molecular docking indicated that BCB and PEA could strongly bind to the site I of HSA, The distances of BCB-HSA and PEA-HSA were 2.90 nm and 4.11 nm, respectively.