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GST全称：Glutathione S-transferase（谷胱甘肽S-转移酶） 分子量： 26 000（单体） 58 500（二体） 以上信息请参考：GE GST Handbook GST的氨基酸序列 MSPILGYWKIKGLVQPTRLLLEYLEEKYEEHLYERDEGDKWRNKKFELGLEFPNLPYYIDGDVKLTQSMAIIRYIADKHNMLGGCPKERAEISMLEGAVLDIRYGVSRIAYSKDFETLKVDFLSKLPEMLKMFEDRLCHK TYLNGDHVTHPDFMLYDALDVVLYMDPMCLDAFPKLVCFKKRIEAIPQIDKYLKSSKYIAWPLQGWQATFGGGDHPPKSDLEVLFQGPLGSPEFPGRLERPH 附：GST的三维结构（pdb ID：1M99）
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Genetic engineers have used glutathione S-transferase to create the so-called 'GST gene fusion system'. Here, GST is used to purify and detect proteins of interest. In a GST gene fusion system, the GST sequence is incorporated into an expression vector alongside the gene sequence encoding the protein of interest. Induction of protein expression from the vector's promoter results in expression of a fusion protein - the protein of interest fused to the GST protein. This GST-fusion protein can then be purified from cells via its high affinity for glutathione. Fusion proteins offer an important biological assay for direct protein-to-protein interactions. For instance, to demonstrate that caveolin (a membrane protein) binds to eNOS (a catalytic protein) a 'GST-caveolin' fusion protein would be generated. Assay beads, coated with the tripeptide glutathione, strongly bind the GST fusion protein (GST-caveolin, in this example). It is noted that, if cavelin binds eNOS, then GST-caveolin will also bind eNOS, and this eNOS will therefore be present on assay beads. GST is commonly used to create fusion proteins. The tag has the size of 220 amino acids, which, compared to other tags like the myc- or the FLAG-tag, is quite big. It is fused to the N-terminus of a protein. However, many commercially-available sources of GST-tagged plasmids include a thrombin domain for cleavage of the GST tag during protein purification. A GST-tag is often used to separate and purify proteins that contain the GST-fusion. GST-fusion proteins can be produced in Escherichia coli, as recombinant proteins. The GST part binds its substrate, glutathione. Agarose beads can be coated with glutathione, and such glutathione-Agarose beads bind GST-proteins. These beads are then washed, to remove contaminating bacterial proteins. Adding free glutathione to beads that bind purified GST-proteins will release the GST-protein in solution. GST系列日志： GST柱材料的参数（GE Glutathione-Sepharose beads性质介绍）
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