Fluorescence Spectroscopy Study On The Changes Of Bovine Serum Albumin In Different Solution Environments

In the past decade,research on protein changes in different solution environments has been a hot research topic.The structure of a protein determines the function of a protein,and the structure of a protein is easily affected by its environment.The use of physical spectroscopy to explore changes in bovine serum albumin in different solution environments provides theoretical guidance for the development of biomedical,biosensing,and bioengineering.This study deeply analyzes the spectral characteristics of bovine serum albumin before and after changes in different solution environments through different research ideas.By changing the environment in which bovine serum albumin solution is located,from steady-state fluorescence to time-resolved fluorescence,and from aromatic amino acids in bovine serum albumin to macromolecular proteins.The main research contents of aromatic amino acids to macromolecular proteins in proteins are as follows:(1)The UV absorption spectra,steady-state fluorescence spectra and timeresolved fluorescence spectra of three amino acids(tryptophan,tyrosine and phenylalanine)and bovine serum albumin in different pH environments are studied.This provides theoretical support for the characteristic parameters of bovine serum albumin fluorescence spectrum.The results show that pH has a certain effect on tryptophan and tyrosine,while phenylalanine is relatively stable in different pH environments.Bovine serum albumin shows five morphological changes at different pH.Bovine serum albumin is in a relatively stable state(N state)in the range of pH 5.0-7.0;the bovine serum albumin is in the pH 4.0-5.0.In the expanded state,the F state is present;the bovine serum albumin in the pH 2.0-3.0 is in an acid-swelled state,which is called the E state;the emission peak in the pH 8.0-10.0 is slightly blue-shifted,and the negative charge begins to aggregate.And the energy of the electronic transition is also beginning to change.At this time,the change is relatively small,called the B state.When the pH rises to 11.0,the red shift tendency of the absorption peak becomes obvious,and the fluorescence lifetime is minimized,which is called the A state.(2)The micro-domain structure changes of bovine serum albumin are analyzed by observing the peak shift,fluorescence intensity and fluorescence lifetime of bovine serum albumin in the three cases of room temperature(25 ?),continuous temperature rise(10 ?-90 ?)and high temperature(90 ?)back to room temperature(25 ?).(3)The steady-state fluorescence spectra and the change of fluorescence lifetime of sodium dodecyl benzene sulfonate,cetyltrimethylammonium bromide and bovine serum albumin mixed solution are analyzed.The results show that there is electrostatic attraction between sodium dodecylbenzene sulfonate and bovine serum albumin,and most likely from the tryptophan residue,the addition of cetyltrimethylammonium bromide promotes bovine serum white as the protein unfolds,the hydrophobicity of the tryptophan residue is further enhanced.Both are static quenching bovine serum albumin.