Wakabayashi K, Ochiai M, Saitô H, Tsuda M, Suwa Y, Nagao M, Sugimura T
Proc Natl Acad Sci U S A. 1983 May;80(10):2912-6. doi: 10.1073/pnas.80.10.2912.
After treatment with nitrite, Japanese soy sauce was strongly mutagenic to Salmonella typhimurium TA100 without S9 mixture. Two precursors of the mutagen were isolated from Japanese soy sauce, and these were identified as (-)-(1S,3S)-1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid [(-)-(1S,3S)-MTCA] and its stereoisomer (-)-(1R,3S)-MTCA. After treatment with nitrite, 1-mg samples of these compounds induced 17,400 and 13,000 revertants of TA100, respectively, without S9 mixture. Quantitative analysis of various kinds of soy sauces produced in Japan showed the presence of 82-678 micrograms of MTCA per ml. The mutagenicities of these compounds with nitrite accounted for 16-61% of the total mutagenicity of soy sauce with nitrite. Most soy sauces produced in the United States were less mutagenic than those produced in Japan and little, if any, of these two precursors of the mutagen was found in them. A major reaction product of (-)-(1S,3S)-MTCA and nitrite was a compound having a nitroso substitution at position N-2, but this compound was not mutagenic. Thus, the mutagen(s) formed from (-)-(1S,3S)-MTCA and nitrite was a minor product(s), and its specific mutagenic activity must be very high.
用亚硝酸盐处理后，日本酱油在无S9混合物的情况下对鼠伤寒沙门氏菌TA100具有很强的致突变性。从日本酱油中分离出了这种诱变剂的两种前体，它们被鉴定为(-)-(1S,3S)-1-甲基-1,2,3,4-四氢-β-咔啉-3-羧酸[(-)-(1S,3S)-MTCA]及其立体异构体(-)-(1R,3S)-MTCA。用亚硝酸盐处理后，1毫克的这些化合物样品在无S9混合物的情况下分别诱导TA100产生17400个和13000个回复突变体。对日本生产的各种酱油进行定量分析表明，每毫升酱油中MTCA的含量为82 - 678微克。这些化合物与亚硝酸盐的致突变性占酱油与亚硝酸盐总致突变性的16% - 61%。美国生产的大多数酱油的致突变性低于日本生产的酱油，并且在其中几乎未发现这种诱变剂的这两种前体。(-)-(1S,3S)-MTCA与亚硝酸盐的主要反应产物是一种在N-2位有亚硝基取代的化合物，但该化合物不具有致突变性。因此，由(-)-(1S,3S)-MTCA和亚硝酸盐形成的诱变剂是次要产物，其特定的致突变活性一定非常高。
