Interaction Of Hormone And Biological Macromolecules And Their Measurement Research

Exogenous hormones can be divided into animal hormones and plant hormone. Dienestrol is a kind of synthetic estrogen and it often used to improve the growth of livestock and milk production etc.2,4-dichlorophenoxyacetic acid (2,4-D) is a synthetic plant growth hormone, is often used to improve fruit quality and prolong the preservation time.But the chemical properties of synthetichormones is relatively stable, which can be easy to produce residues in animals, plants and water environment, which will cause a potential threat to human health.Study the interaction of the exogenous hormones and biological molecules and constructing suitable sensors based on this interaction is thus very important.The mainimportant biomacromolecules include proteins, nucleic acids, lipids and polysaccharides. Enzyme is one kind of protein that has special catalytic effect in the organism, what’s more, it also plays an important role in maintainthe biochemical reaction of organism and metabolism.Various small drug molecules, which will go into the body, could damagethe structure and function of proteinand affect the normalmetabolism of human body. Therefore, studying the interaction of hormone and protein as well as measuring the hormone residuals is very necessary.In this thesis, we study the interaction mechanism of dienestrol and catalaseat the molecular level, the immobilization of biomacromolecules on different substrate the construction of different sensors for 2,4-D detection.This thesis mainly includes four chapters.Chapter 1:In this chapter, we mainly introduceseveral kinds of common hormones and the structure, properties and applications of biomacromolecules. It also summarizes the main research method for the interaction of hormones and biomacromolecules, the study of enzyme immobilization methods and the choice of carrier, the determination method of hormone residuesand the design ideas and innovations of this article.Chapter 2:we use serious methods to study the interaction mechanism of catalase and dienestrol. The experiment results show that the fluorescence of catalase was quenched by dienestrol with a static quenching process. According to the fluorescence spectra, we can obtain the binding constant, binding points, binding distance and the thermodynamic parameters. The addition of dienestrol changed the microenvironment of the amino acid residues and secondary structure of catalase. It also discusses the influence on the catalytic activity of catalase by dienestrol.The results show that the inhibition of dienestrol and catalase is competitive.Chapter 3:In this chapter, wesynthetizedthe Fe3O4-NH2-CS magnetic nanocomposites by adsorption-crosslinking methodand immobilize catalase onto the surface of this material. According to the inhibition of catalase by 2,4-D, an enzyme inhibition sensor was built to determine the content of 2,4-D in samples. The advantages of this method are simple operation, good stability, high sensitivity, high repetition utilization rate, and low cost. The linear range of enzyme inhibition biosensor for 2,4-D detection was from 5.0×10-8 mol/L to 1.05×10-6 mol/L with a detection limit of3.0×10-8mol/L. It can be used to detect the residues of 2,4-D in actual samples.Chapter 4:In this chapter, we use cryogel as the carrier to immobilize Horseradish peroxidase (HRP). HRP can catalyze the oxidation of TMB to blue substrate in the presence of H2O2. According to the inhibition ofHRP by 2,4-D, an inhibition sensor was constructed to determine 2,4-D in samples. The method for 2,4-D determination showed good stability, sensitivity and repetition rate.The linear range of enzyme inhibition biosensor for 2,4-D detection was from 5.0×10-8 mol/L to 1.2×10-6 mol/L with a detection limit of 3.0×10-8 mol/L. It can be used for the rapid determination of 2,4-D residues in practical samples.