Knize M G, Happe J A, Healy S K, Felton J S
Mutat Res. 1987 May;178(1):25-32. doi: 10.1016/0027-5107(87)90082-0.
Two mutagens isolated from fried-beef patties were compared to a series of synthetic structural isomers of 2-aminodimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-aminotrimethylimidao[4,5-f]quinoxaline (DiMeIQx). Comparison by NMR spectrometry and HPLC coelution showed that one beef mutagen (molecular weight of 213) was identical to the 8-MeIQx isomer not the 7-Me isomer. Another quinoxaline beef mutagen, having 3 methyl groups (molecular weight of 227), had an NMR spectrum different from the 5,8- or 7,8-DiMeIQx isomers, but not clearly distinguishable from the 4,8- or 4,7-DiMeIQx isomers. The HPLC separation of the DiMeIQx isomers and subsequent addition of the beef mutagen showed the beef-derived compound to coelute with the 4,8-DiMeIQx and not with the 4,7-DiMeIQx. The number and position of methyl groups was responsible for a 7-fold range of mutagenic response in the Ames/Salmonella assay. In conclusion, the major quinoxaline mutagens isolated from fried beef were identified as 8-MeIQx and 4,8-DiMeIQx isomers.
将从煎牛肉饼中分离出的两种诱变剂与2-氨基二甲基咪唑并[4,5-f]喹喔啉（MeIQx）和2-氨基三甲基咪唑并[4,5-f]喹喔啉（DiMeIQx）的一系列合成结构异构体进行了比较。通过核磁共振光谱法和高效液相色谱共洗脱分析表明，一种牛肉诱变剂（分子量为213）与8-MeIQx异构体相同，而非7-Me异构体。另一种含有3个甲基的喹喔啉类牛肉诱变剂（分子量为227），其核磁共振光谱与5,8-或7,8-DiMeIQx异构体不同，但与4,8-或4,7-DiMeIQx异构体没有明显区别。对DiMeIQx异构体进行高效液相色谱分离，随后加入牛肉诱变剂，结果显示源自牛肉的化合物与4,8-DiMeIQx共洗脱，而不与4,7-DiMeIQx共洗脱。在艾姆斯/沙门氏菌试验中，甲基的数量和位置导致诱变反应范围相差7倍。总之，从煎牛肉中分离出的主要喹喔啉类诱变剂被鉴定为8-MeIQx和4,8-DiMeIQx异构体。
