Iron-dependent formation of homocysteine from methionine and other thioethers
Iron-dependent formation of homocysteine from methionine and other thioethers
复制标题
DOI：
10.1038/sj.ejcn.1602665
复制
发表时间：
2007-12-01
影响因子：
4.7
通讯作者：
Tamura, T.
中科院分区：
文献类型：
--
作者：
Baggott, J. E.;Tamura, T.
目的：我们测试了是否同型半胱氨酸是由甲硫氨酸和其他硫醚在体外和体内形成的，因为甲硫氨酸可以被化学脱甲基到homocysteine.Design：在体外研究中，化学转化的硫醚（甲硫氨酸，S-腺苷同型半胱氨酸和胱硫醚）到同型半胱氨酸进行了测量，在各种有氧条件下。在人类中，口服蛋氨酸（0.17 mmol/kg体重）负荷试验，并没有口服铁剂量（硫酸亚铁，13 mmol/kg）performed.Setting：一所大学设置在伯明翰，AL，USA.Subjects：A总共有五个健康的成年受试者volunteer.Results：甲硫氨酸，S-腺苷同型半胱氨酸或胱硫醚与螯合铁的体外孵育导致同型半胱氨酸的形成。这些转化是铁和pH依赖性的（最佳pH值在5.0和6.0之间），也是螯合剂依赖性的。在人类中，口服蛋氨酸负荷试验导致血浆总同型半胱氨酸浓度的曲线下面积增加45%，当铁与methion.Conclusion：我们的数据表明，铁依赖的同型半胱氨酸的化学形成可以在体内发生，并有助于血浆总同型半胱氨酸池，因为这种形成可以不断发生。我们假设血浆总同型半胱氨酸浓度部分反映了体内非蛋白结合铁。
Objective: We tested whether homocysteine is formed from methionine and other thioethers in vitro and in vivo, because methionine can be chemically demethylated to homocysteine.Design: In in vitro studies, chemical conversions of thioethers (methionine, S-adenosylhomocysteine and cystathionine) into homocysteine were measured under various aerobic conditions. In humans, oral methionine (0.17 mmol/kg body weight) loading tests with and without an oral iron dose (ferrous sulfate, 13 mmol/kg) were performed.Setting: A university setting in Birmingham, AL, USA.Subjects: A total of five healthy adult subjects volunteered.Results: The in vitro incubation of methionine, S-adenosylhomocysteine or cystathionine with chelated iron resulted in the formation of homocysteine. These conversions were iron- and pH-dependent (pH optima between 5.0 and 6.0) and it was also chelator-dependent. In humans, oral methionine loading tests resulted in a 45% increase in the area-under-the-curve for plasma total homocysteine concentrations, when iron was given together with methionine.Conclusion: Our data suggest that iron-dependent chemical formation of homocysteine can occur in vivo, and contribute to the plasma total homocysteine pool, since this formation can occur ceaselessly. We hypothesize that plasma total homocysteine concentrations reflect, in part, non-protein-bound iron in the body.