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胶束电动色谱法测定蛋白质表面自由氨基 被引量:2
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作者 毛文学 苏勇 康经武 《有机化学》 SCIE CAS CSCD 北大核心 2006年第5期707-710,共4页
建立了一种毛细管电泳测定蛋白质分子表面自由氨基的方法.配制蛋白质样品溶液,分取5等份,分别加入过量的不同物质的量的芴甲氧羰酰琥珀酰亚胺(FMOC-OSu)溶液,室温下反应30min后,用胶束电动色谱测定蛋白质溶液中剩余的FMOC-OSu的峰面积.... 建立了一种毛细管电泳测定蛋白质分子表面自由氨基的方法.配制蛋白质样品溶液,分取5等份,分别加入过量的不同物质的量的芴甲氧羰酰琥珀酰亚胺(FMOC-OSu)溶液,室温下反应30min后,用胶束电动色谱测定蛋白质溶液中剩余的FMOC-OSu的峰面积.以FMOC-OSu的峰面积对加入的FMOC-OSu的物质的量做校准曲线.该直线外推到峰面积为0时所对应的FMOC-OSu物质的量即为参加反应的蛋白质表面的氨基的物质的量.因此可以计算出蛋白质表面的氨基数目.用甘氨酸检验了本方法的可靠性.以牛血清白蛋白为蛋白质模型,测得其表面氨基数为32,和文献报道值一致.该方法简单易行并且反应条件温和,可用于测定蛋白质修饰过程中的平均修饰度. 展开更多
关键词 胶束电动色谱 蛋白质自由氨基 氨基的测定
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Effects of free radicals and amyloid β protein on the currents of expressed rat receptors in Xenopus oocytes
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作者 黄福南 李文彬 +6 位作者 张炳烈 崔旭 韩志涛 房征宇 蔡竖平 尹岭 王鲁宁 《Chinese Medical Journal》 SCIE CAS CSCD 2001年第3期20-23,103,共5页
Objective To investigate the effects of free radicals (FRs) and amyloid β protein 1 40 (Aβ 1 40 ) on the functions of expressed neurotransmitter receptors (NRs) in Xenopus oocytes Methods Total RNA and ... Objective To investigate the effects of free radicals (FRs) and amyloid β protein 1 40 (Aβ 1 40 ) on the functions of expressed neurotransmitter receptors (NRs) in Xenopus oocytes Methods Total RNA and messenger RNA (mRNA) was prepared from 3 month old Wistar rat brain tissues with Promega kits and microinjected into maturated Xenopus oocytes (stages Ⅴ Ⅵ) with 50?nl (50?ng) for each oocyte The microinjected oocytes were incubated with modified Bath's solution at 19 0℃±1 0℃ for receptor expression and their currents were recorded with double electrode voltage clamp technique Superoxide anion free radicals (SAFRs) were produced via a reaction system (HPX/XO) with hypoxanthine (HPX, 0 05?mol/L) and xanthine oxidase (XO, 0 1?U/L) In order to observe the effects of Aβ and SAFRs on the expressed glutamate receptor, HPX/XO and Aβ 1 40 were added to incubation solution at 12?h, 24?h and 96?h before recording Results The results showed that the oocytes expressed functional NRs originating from rat brain tissues These NRs included muscarinic acetylcholine (mACh), glutamate (Glu), dopamine (DA), serotonin (5 HT) and γ aminobutyric acid (GABA) The current characteristics of expressed receptors were inward currents carried by chloride ion with their equibrilium potentials close to -22?mV The extent of effect on the current of expressed glutamate receptor from rat brain was different among different Aβ concentrations and incubation times Aβ 1 40 at a concentration of 20?nmol/L had little effect on the currents of expressed rat brain glutamate receptors up to 24?h of incubation period; but the currents of glutamate receptor were significantly decreased (25% off, P <0 01) in the treatment of 60?nmol/L Aβ 1 40 over 24?h Moreover, when 20?nmol/L Aβ 1 40 was co incubated over 12?h with SAFRs produced by the reaction system of HPX/XO, it was found that the currents of expressed rat brain glutamate receptors had been changed markedly When the oocytes were co treated with 60?nmol/L Aβ 1 40 and SAFRs over a period of 12?h, the currents of glutamate receptor significantly decreased (21% off, P <0 05), and the decreased percentage reached 52% over 24?h co treatment with 60?nmol/L Aβ 1 40 and SAFRs In addition, vitamin E had a partial effect against this inhibitory effect Conclusion The results suggest that Aβ has a kind of inhibitory effect upon the current of the glutamate receptor, similar to the effects of free radicals The effects can be antagonized by vitamin E These imply that Aβ may play a role via inhibiting receptor function in the pathophysiology of Alzheimer's disease 展开更多
关键词 amyloid β protein · free radicals · neurotransmitter receptor · glutamate · Alzheimer's disease
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