Synthesis and structure characterization of selenium metabolites
Synthesis and structure characterization of selenium metabolites
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DOI：
10.1039/a707597i
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发表时间：
1998-05-01
期刊：
影响因子：
4.2
通讯作者：
Higashi, RM
中科院分区：
文献类型：
--
作者：
Fan, TWM;Lane, AN;Higashi, RM
痕量有机硒代谢物的难以测定和缺乏商业标准一直是分子水平理解硒的地球化学、生态毒理学和营养学的主要障碍，特别是在水生生态系统中。为了克服这个问题，合成了三种重要的挥发性烷基硒化物前体，包括二甲基硒丙酸盐（DMSeP），其仅被假定存在于自然界中。2-D多核NMR，电喷雾MS和GC-MS方法的组合被用来鉴定合成制剂中的DMSeP，甲基硒代蛋氨酸和甲基硒代半胱氨酸，而无需广泛的清理。采用碱性氢消除试验结合气相色谱-质谱联用技术对二甲基硒（DiMSe）和二甲基二硒（DMDSe）的释放模式进行了诊断测定。的DMSe释放模式的DMSeP证实了存在的DMSeP样化合物的生物量的100毫克1（-1）硒处理的小球藻先前调查。甲硅烷化-GC-MS测定硒代蛋氨酸，硒代半胱氨酸和甲基硒代半胱氨酸在一个标准的混合物与硒代蛋氨酸的检测限优于1 pmol每0.5 μ l注射体积进行了测试。该方法被应用于小球藻培养物的蛋白质级分的酸消化物的分析。结果表明，硒代甲硫氨酸在小球藻生物量中仅占总硒的一小部分，但其蛋白质结合硒的比例大于70%，揭示了硒挥发与硒代甲硫氨酸蛋白质结合的代谢关系。这方面的知识是至关重要的，在硒地球化学，生态毒理学和原位生物修复方案的发展。
The difficulty in determining trace-level organoseleno metabolites and the lack of commercially available standards have been major barriers to a molecular-level understanding of Se biogeochemistry, ecotoxicology and nutrition, particularly in aquatic ecosystems, To overcome the problem, three important precursors of volatile alkyl selenides were synthesized, including dimethylselenonium propionate (DMSeP), which has only been postulated to exist in nature. A combination of 2-D multinuclear NMR, electrospray MS and GC-MS methods was employed to identify DMSeP, methylselenomethionine and methylselenocysteine in synthetic preparations without extensive clean-up. An alkaline hydroelimination test coupled with GC-MS analysis for the release pattern of dimethyl selenide (DiMSe) and dimethyl diselenide (DMDSe) was developed for a diagnostic determination of the three products. The DMSe release pattern of DMSeP confirmed the presence of a DMSeP-like compound in the biomass of 100 mg l(-1) Se-treated Chlorella investigated previously. Silylation-GC-MS was tested for the determination of selenomethionine, selenocysteine and methylselenocysteine in a standard mixture with a detection limit of better than 1 pmol per 0.5 mu l injection volume for selenomethionine. This method was applied to the analysis of the acid digest of the proteinaceous fraction of the Chlorella culture. Selenomethionine was found to contain > 70% of the protein-bound Se, although this constituted only a minor fraction of the total Se in the Chlorella biomass, These findings revealed the metabolic relationship between Se volatilization and selenomethionine incorporation into proteins. This knowledge is critical to advancement in Se biogeochemistry, ecotoxicology and the development of in situ bioremediation schemes.