| Abstract: | 本實驗將麩胱甘太轉移?glutathione S-transferase, 胞株C6/36純化出 來, 分別以四硝基甲烷, 苯丙二醛, 磷酸比哆酸,-乙醯基咪脞處理, 觀察 GST的變化. 結果發現, GST 甲烷, 苯丙二醛及磷酸比多醛所抑制, 且此 抑制作用會被one, glutathionyl 2,4-dinitrobenzene, ethacrynic acid 和O護, 這表示 GST 內之酪胺酸, 精胺酸及離胺酸可能與 GST 活性 有關, 的胺基酸可能皆位於 G-site 及 H-site 內, 其中的酪胺酸可能 與 它親電性基質的結合有關; 精胺酸也與親電性基質的結合有關, 但與 合無關; 離胺酸則與兩種基質的結合皆無關. 焦炭酸二乙酯及 N-k改變 GST 的活性, 表示組織胺酸與半胱胺酸可能與 GST 的活性無關.
Glutathione S-transferase (GST) which was purified from Aedesline, C6/36, was treated with tetranitromethane (TNM), pyridoxal 5-phosphate (PLP) diethylpyrocarbonate (DEPC) andle. The tyrosine-specific reagent TNM inactivated the enzyme- hexylglutathione, glutathuonyl 2,4- dinitrobenzene (GSDNB) andprotected against this inactivation. Binding affinity forelectrophilic substrates of TNM-treated GS was significantly greater than those of untreated enzyme. Thesethat tyrosine in the glutathine binding site (G-site) andng site (H-site) may be functionally important in catalysis andng. From the same method, arginine in the G-site and H-site mayimportant in catalysis and that this residue in the H-site may bebstrate binding. Lysine in G-site and H-site may not be importantnding but may be funtionally important in catalysis. The histidine- specificd cysteine-specific reagent N-acetylimidazole did not inactivatendicating that histidine and cysteine are not essential in |
