Loeppky R N, Tomasik W, Eisenbrand G, Denkel E
Department of Chemistry, University of Missouri, Columbia 65211.
IARC Sci Publ. 1987(84):94-9.
alpha-Nitrosamino aldehydes are highly reactive compounds which are directly-acting mutagens and are capable of facile transnitrosation to secondary and primary amines. The latter lead reactions to deamination. N-Nitrosobutyl(2-oxoethyl)amine (NBOEA) undergoes spontaneous decomposition in buffer at pH greater than 7 (25 degrees C) to give glyoxal and products implicating the formation of the butyl diazonium ion. NBOEA reacts with guanosine to produce xanthosine (by deamination), 7-butylguanosine and the 1,N2 glyoxal adduct, among other products. All beta-nitrosaminoethanols investigated undergo liver alcohol dehydrogenase-catalysed oxidation to their corresponding aldehydes. Several of these aldehydes have been shown to be directly-acting mutagens. These data provide strong evidence for an alternative carcinogenic bioactivation route for nitrosamines which does not involve alpha-oxidation.
α-亚硝基氨基醛是高活性化合物，它们是直接作用的诱变剂，能够容易地将亚硝基转移至仲胺和伯胺。后者引发脱氨基反应。N-亚硝基丁基（2-氧代乙基）胺（NBOEA）在pH大于7（25℃）的缓冲液中会自发分解，生成乙二醛以及涉及丁基重氮离子形成的产物。NBOEA与鸟苷反应会生成黄苷（通过脱氨基作用）、7-丁基鸟苷以及1,N2-乙二醛加合物等产物。所研究的所有β-亚硝基氨基乙醇都会在肝醇脱氢酶的催化下氧化为其相应的醛。其中几种醛已被证明是直接作用的诱变剂。这些数据为亚硝胺的一种不涉及α-氧化的替代性致癌生物活化途径提供了有力证据。
