Studies On Interaction Between Epi-catechin Gallate And Bovine Serum Albumin And Effects Of Different Metal Ions On The Reation

With the increasing of unhealthy factors,malignant tumors become one of the greatest threats to human health,and their treatments remain a worldwide problem.So does diabetes mellitus.The early prevention and treatment of disease is critical,and Catechin can be used for the treatment of malignant tumors as well as diabetes mellitus.Among them,epi-catechin gallate has a strong antitumor activity therein,can inhibit the proliferation of cancer cells,which has been widespread concern recently.Metal ions are widely distributed in environment and can enter the body in various ways without degradation,which has good or bad influences.In plasma,drugs were absorbed into the blood circulation and combine with the transporter for example bovine serum albumin.The prensence of different kinds of metal ions play an important role in the interaction among them,and affect the interaction of epi-catechin gallate and serum albumin.In the meanwhile,the involvement of drugs can also affect their interactions with transport proteins.Spectroscopic methods are useful for obtaining conformation,binding parameters,binding sites and influence of coexisting substances,and other useful information because of their advantages,such as less dosage,simple operation and high sensitivity.The paper were divided into four parts:1.Studies of the interaction between epi-catechin gallate and bovine serum albumin in the presense of low-valent metal ionsFluorescence spectroscopy and circular dichroism spectroscopy and UV-vis absorption spectroscopy were used to explore the spectral changes and the second structure changes of protein interacted with epi-catechin gallate at four temperatures conditions.And from the fluorescence data,the main type of quenching was static quenching mechanism.The number of binding sites was atound 1.The force types were electrostatic attraction,hydrophobic force and hydrogen band.Meanwhile,in the presence of magnesium ions promoted binding effects,while others were on the controry.2.Studies of the interaction between Fe(III),Cr(III)and and bovine serum albumin and in the presence of epi-catechin gallate on the reactionsSpectral methods were used in exploring the interaction between trivalent metal ions of iron and chromium with albumin respectively,also exploring the interactions between trivalent metal ions and protein under the effect of epi-catechin gallate,and also exploringthe interaction between epi-catechin gallate and protein coexisted with trivalent metal ions.According to the fluorescence data,it can investigate the main types of quenching of the binary and ternary systems were all static quenching.Using labeled drugs warfarin and ibuprofen marked two different sites on protein respectively,and identified the competition between epi-gallocatechin gallate and trivalent iron ions on the protein.3.Studies on the interaction between Ca(II),Sr(II)and bovine serum albumin and effects of epi-catechin gallateThe fluorescence spectra and the unchanged secondary structure of BSA binded calcium ions and strontium ions were studied by fluorescence quenching spectroscopy,synchronous fluorescence spectroscopy and UV-vis absorption spectroscopy at four temperatures.And from the fluorescence data,the main types of quenching were dynamic quenching.The number of binding sites was atound 1.The effect of epi-gallocatechin gallate in ternary systems on the interaction between these two alkaline earth metal ions and protein were discussed,respectively.The force types were electrostatic attraction between calcium ions or strontium ions and proteins for finding decreased effects on the interaction.Synchronous fluorescence spectroscopy was used to determine the same binding capacity of calcium and strontium ions with tyrosine and tryptophan residues in protein respectively.4.Studies of the interaction between four light lanthanide rare earth metal ions with bovine serum albuminFluorescence spectroscopy,circular dichroism spectroscopy and UV-vis absorption spectroscopy methods were applicated to explore the interaction between four trivalent light lanthanides rare earth metal ions of lanthanum,cerium,neodymium and samarium with bovine serum albumin under four temperature respectively.The main types of quenching were all static quenching.The force types were electrostatic attraction.The secondary structure changed.The influence of epi-gallocatechin gallate on the interactin between four trivalent light lanthanides rare earth metal ions and proteins in ternary systems were discussed in secondary structural change,finding that it slowed the change down helpfully.