Elucidation of a Novel Bioactivation Pathway of a 3,4-Unsubstituted Isoxazole in Human Liver Microsomes: Formation of a Glutathione Adduct of a Cyanoacrolein Derivative after Isoxazole Ring Opening
作者:Jian Yu、James J. Folmer、Valerie Hoesch、James Doherty、James B. Campbell、Doug Burdette
DOI:10.1124/dmd.110.036285
日期:2011.2
cyanoacrolein derivative (M3). The same adduct also is formed when M1, generated in 0.1 N NaOH aqueous solution, reacts with formaldehyde and GSH. (13)C-labeled methanol was used to confirm that methanol from the drug stock solution was oxidized by liver microsomal enzymes to formaldehyde and the carbon atom from methanol was finally incorporated in the corresponding GSH adduct. The formation of isoxazole ring-opened
对异恶唑环的生物转化的研究表明,含有C3取代的异恶唑或1,2-苯并恶唑的分子可以经过两电子还原环裂解形成亚胺。在不存在C 3取代基的情况下,异恶唑环通过C 3质子的去质子化,然后进行NO键断裂而打开,从而生成α-氰基烯醇类似物。我们报告了人类肝脏微粒体中3,4-未取代的异恶唑的新型生物激活途径的鉴定。酶催化的人肝微粒体中N-(((2-异丙基-7-甲基-1-氧代异吲哚-5-基)甲基)异恶唑-5-羧酰胺(P)的3,4-未取代异恶唑环的酶催化裂解后,形成的α-氰基烯醇(M1)与甲醛缩合,生成α,β-不饱和Michael受体中间体(氰基丙烯醛衍生物VII),进一步与谷胱甘肽的半胱氨酰硫醇反应生成氰基丙烯醛衍生物(M3)的GSH加合物。当在0.1 N NaOH水溶液中生成的M1与甲醛和GSH反应时,也会形成相同的加合物。(13)C标记的甲醇用于确认药物储备液中的甲醇被肝微粒体酶氧化为甲醛,并且甲醇中