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高压液相色谱分析DNS-[^(75)Se]蛋氨酸 被引量:2
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作者 吴叔筠 于洁 赖运琅 《色谱》 CAS CSCD 北大核心 1989年第3期169-170,173,共3页
蛋氨酸属氨基酸类,无紫外吸收。[^(75)Se]蛋氨酸为其硒标记化合物,被广泛用作胰腺扫描、甲状腺扫描,某些肝肿瘤、恶性肿瘤的阳性扫描,恶性淋巴瘤的测定,胎盘机能的测定和人体内新陈代谢的研究等。 为提高分离效率,缩短分析时间,发展了... 蛋氨酸属氨基酸类,无紫外吸收。[^(75)Se]蛋氨酸为其硒标记化合物,被广泛用作胰腺扫描、甲状腺扫描,某些肝肿瘤、恶性肿瘤的阳性扫描,恶性淋巴瘤的测定,胎盘机能的测定和人体内新陈代谢的研究等。 为提高分离效率,缩短分析时间,发展了柱前衍生化法。衍生化试剂1-二甲基胺萘-5-磺酰氯(DNS—C1)是示踪量测定氨基酸的最佳衍生化试剂,反应灵敏度比茚三酮高几个数量级。其衍生物制备迅速,重现性好,有紫外吸收,可利用高压液相色谱进行分离分析。 展开更多
关键词 () DNS-Cl柱衍生 HPLC
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The Conditions for Se-Enzymes, NO, cGMP and LDL to be Formed and How They are Connected with Each Other
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作者 Birgit Elisabeth Swenson 《Journal of Chemistry and Chemical Engineering》 2014年第3期278-285,共8页
Transportation of energy and substances is fundamental for the conditions of life. The energy from metabolised food is yielded at the reduction of oxygen by the assistance of Se-enzymes. Activated Se-enzymes contain a... Transportation of energy and substances is fundamental for the conditions of life. The energy from metabolised food is yielded at the reduction of oxygen by the assistance of Se-enzymes. Activated Se-enzymes contain an electron conducting Se-link with elemental Se bounded to Se-cys (Se-cystein) that prevents electron transferring (autoxidable) agents, as arginine, from oxidations. NO is formed from e.g. arginine during the passive state of a Se-enzyme. With NO, instead of O2, bounded to a hem group, destroying oxidations are avoided. This is the role of NO. A nerve signal is activated by the GTP (guanosine triphosphate)-induced triggered transformation of cGMP (cyclic guanosine monophosphate) into GMP, closing the sodium channels. When GTP is consumed, the opposite reaction takes place. The direct influence of the GMP/cGMP quote on a nerve signal makes GMP/cGMP equal to EDHF (endothelium-derived hyperpolarizing factor). Part of the energy from food is stored and transported in the form of acetyl groups, building up many important molecules of which LDL (low density lipoprotein) is one, containing cholesteryl esters. These are brought in to the cell, decomposed to acetyl groups generating hydrogen, H, making LDL to an essential substance. High levels are connected to impaired energy yielding reactions, perhaps related to low levels of some substances, especially to one or both forms of Se. The necessity of a Se-link and NO induced protection against oxidations by reducible oxygen can no longer be neglected. 展开更多
关键词 Se-enzymes Se-toxicity formation of NO formation of cGMP EDHF cholesteryl esters from LDI. .
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土壤酶对外源有机硒和无机硒的动态响应 被引量:11
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作者 史雅静 史雅娟 +5 位作者 王玉荣 李田春 周宝春 谢勇 徐福友 梁若玉 《环境科学学报》 CAS CSCD 北大核心 2018年第3期1189-1196,共8页
通过室内非作物连续培养,研究了不同剂量、不同形态外源硒(亚硒酸钠、硒代蛋氨酸)对土壤脲酶、蔗糖酶、中性磷酸酶活性影响的动态变化过程.结果表明,低剂量(10 mg·kg^(-1))无机硒(亚硒酸钠)对土壤脲酶和蔗糖酶活性有先激活后抑制作... 通过室内非作物连续培养,研究了不同剂量、不同形态外源硒(亚硒酸钠、硒代蛋氨酸)对土壤脲酶、蔗糖酶、中性磷酸酶活性影响的动态变化过程.结果表明,低剂量(10 mg·kg^(-1))无机硒(亚硒酸钠)对土壤脲酶和蔗糖酶活性有先激活后抑制作用,对土壤中性磷酸酶活性有激活作用.而相同剂量有机硒(硒代蛋氨酸)处理时,3种酶均表现为不同程度的激活状态.高剂量(>30 mg·kg^(-1))无机硒(亚硒酸钠)处理时,3种酶活性均表现先激活后抑制,其中对脲酶影响最大,对蔗糖酶影响次之,对中性磷酸酶影响最小.而施入高剂量(>30 mg·kg^(-1))有机硒(硒代蛋氨酸)后,对土壤中脲酶、蔗糖酶的激活作用明显大于无机硒的影响,但对磷酸酶的影响不明显.试验充分说明施入不同剂量、不同形态的外源硒,土壤酶活性表现出不同的动态响应,并且有机硒比无机硒更有利于土壤微生物的生长,能提高土壤酶活性,促进N、P、C养分在土壤生态系统的循环.用有机硒替代无机硒作为外源硒源,有望成为未来发展方向. 展开更多
关键词 污染 无机(亚钠) 有机() 土壤酶活性 相对抑制率
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