The interaction between white matter and protein is a major component of cell biochemical reaction network, and protein-protein interaction network and transcription regulation network are of great significance for regulating cells and their signals. A research method on the interaction between protein and protein in the original spaces space is transferred, which is the first one in the classified catalogue of experimental skills. \xd\\xd\ 1. Yeast two-hybrid system \xd\ Yeast two-hybrid system is an important method widely used in the study of protein interaction genomics. The principle is that when the target protein and the bait protein specifically bind, the bait protein binds to the promoter of the reporter gene to start the expression of the reporter gene in yeast cells. If the expression product of the reporter gene is detected, it means that there is interaction between them, otherwise there is no interaction between them. After miniaturization and array, this technique can be used to study the interaction between large-scale protein. In practical work, people have developed single hybrid system, three hybrid system and reverse hybrid system according to their needs. Angermayr and others designed a two-hybrid system mediated by SOS protein. The function of membrane protein can be studied, which enriches the function of yeast two-hybrid system. In addition, the function of yeast two-hybrid system has been extended to the identification of protein. \xd\\xd\ II. Phage display technology \xd\ The DNA sequence of a monoclonal antibody is connected to the gene encoding phage coat protein. When the phage grows, the corresponding monoclonal antibody is expressed on the surface, and then the phage passes through the column. If the target protein is contained on the column, it will specifically bind with the corresponding antibody. This is called phage display technology. This technique is also mainly used to study the interaction between protein. It not only has the characteristics of Qualcomm quantity and simplicity, but also has the advantages of directly obtaining genes, screening complex mixtures with high selectivity, and directly evaluating the specificity of mutual binding by changing the conditions in the screening process. At present, the cDNA libraries of two special cell lines, human and mouse, have been displayed by using optimized phage display technology, and the signal molecules in the signal transduction pathway of human epithelial growth factor have been isolated. \xd\ III. Plasma * * vibration technology \xd\ Surface Plasmon Resonance (SPR) has become a new means in the study of protein interaction. Its principle is to use a nano-scale film to adsorb "bait protein". When the protein to be detected is combined with the bait protein, the vibration properties of the film will change, and the combination of the two proteins can be known through detection. The advantage of SPR technology is that it does not need markers or dyes, and the reaction process can be monitored in real time. The assay is rapid and safe, and can also be used to detect the interaction between protein-nucleic acid and other biological macromolecules. \xd\ IV. Fluorescence energy transfer technology \xd\ Fluorescence vibrational energy transfer (FRET) is widely used to study the distance between molecules and their interactions; Combined with fluorescence microscope, the spatio-temporal information about protein, lipids, DNA and RNA in living organisms can be obtained quantitatively. With the development of green fluorescent protein (GFP), it is possible for FRET fluorescence microscope to measure the dynamic properties of molecules in living cells in real time. A simple method for quantitatively measuring FRET efficiency and the distance between donor and acceptor is proposed, which only needs to use a set of filters and measure a ratio, and eliminates the cross-talk between spectra by using the emission spectra of donor and acceptor. This method is simple and rapid, and can quantitatively measure the efficiency of FRET and the distance between donor and acceptor in real time, especially for donor-acceptor pairs based on GFP. \xd\ V. Antibody and protein array technology \xd\ The appearance of protein chip technology brings new ideas to protein's proteomics research. One of the main contents of protein's proteomics research is to study the quantitative change, miniaturization, integration and Qualcomm quantification of protein levels in different physiological states. The antibody chip is a very good research tool, and it is also the fastest developing chip in the chip, and its technology has become increasingly mature. Some of these antibody chips have been developed in clinical applications, such as tumor marker antibody chips, and many have been applied in various fields. \xd\ VI. Immuno-* * precipitation technology \xd\ Immuno-* * precipitation is a technology mainly used to study the interaction between protein and protein [/url]. Its basic principle is that an antibody against the protein of interest is added to the cell lysate, and then staphylococcus aureus protein A(SPA) bound to Pansobin beads specifically combined with the antibody is added after incubation. If there is positive and interest in the cell, Such a complex can be formed: "target protein-interest protein-anti-interest protein antibody-SPA\|Pansobin", because SPA \ | PANSOBIN is relatively large, so that the complex can be separated during centrifugation. After denaturing polyacrylamide gel electrophoresis, the four components of the complex were separated again. Then, Western blotting method was used to detect what the target protein was and whether it was a predicted protein. The target protein obtained by this method is naturally combined with the protein of interest in cells, which conforms to the actual situation in vivo and the obtained protein has high reliability. However, this method has two defects: first, the combination of the two protein may not be a direct combination, but there may be a third party acting as a bridge in the middle; Second, it is necessary to predict what the target protein is before the experiment in order to select the antibody to be detected finally. Therefore, if the prediction is incorrect, the experiment will not get the result, and the method itself is risky. \xd\ VII. pull-down technology \xd\ There are two types of protein interaction: firm interaction and temporary interaction. Solid interactions are common in multi-subunit protein complexes, and it is best to study them by immune precipitation (Co-IP), Pull-down technique or Far-western method. Pull-down technology uses immobilized, labeled bait protein or tag protein (biotin-,PolyHis- or GST-) to catch the protein interacting with it from cell lysate. Pull-down technology can be used to determine the interaction between known proteins and fished proteins or purified related proteins, and the interaction between proteins can be detected from in vitro pathway or translation system.