梅納褐變反應產物誘導DNA變異之研究   全文下載

Studies on DNA Mutagenesis Mediated by Maillard Reaction Products

本實驗利用in vltro製備之梅納褐變反應產物（MRPs）與質體pUC12分子反應，在濃度0.025M至1M之葡萄糖及離胺酸MRPs，其與pUC12之反應液於反應時間 分鐘至24小時內，皆會導致pUC12之轉形功能下降。檢視反應24小時內MRPs與pUC12反應液裡的pUC12 DNA電泳圖譜，並未發現任何DNA圖譜型式的改變。延長MRPs與pUC12之反應時間至4天及12天，反應液裡DNA之轉形效率分另別為3.2%及0.15%，反應12天之反應液裡pUC12之轉形效率明顯下降。此情形亦發生於生物蛋白lens-crystallin protcin及lysozyme分別與葡萄糖反應二個月之MRPs，其與pUC12反應4天及12天後pUC12之轉形效率，反應12天者較之反應4天者低數倍。此些MRPs與pUC12反應液經酒精變性處理並復溶於TE緩衝液，則反應液中pUC12之轉形效率較之不經酒精變性處理者增加數十倍，此情形亦見於反應不超過24小時的葡萄糖及離胺酸MRPs與pUC12之反應液。

A glucose-lysine Maillard model system was prepared and its reaction products (MRPs) obtained. Reaction of the 0.025M to IM glucose-lysine MRPs with plasmid pUC12, resulted in lowered transformation efficiency of pUC12 throughout the reaction time which ranged from five minutes to twenty-four hours. Attempts to compare the pUC12 DNA pattern after being incubated with the MRPs, showed no size change of the DNA as evidenced by gel electrophoresis. Following increased incubation time of MRPs and pUC12 DNA from four to twelve days, showed transformation efficiencies of the pUC12 to be 3.2% and 0.15%, respectively. Transformation efficiencies of pUC12 incubated with MRPs for 12 days were several folds lower than that incubated for four days. Following denaturation of the incubation mixtures of pUC12 and MRPs by ethanol precipitation and renaturation in Tris-EDTA buffer, the transformation efficiency of pUC12 was increased by more than ten folds. This phenomenon was also found in those of the pUC12 incubated with glucose-lysine MRPs within twenty-four hours.