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BSA-standard

BSA蛋白标准品

Company: Thermo Fisher Scientific
Catalog#: 23209
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Guanine Nucleotide Exchange Assay Using Fluorescent MANT-GDP
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Date:
2018-04-05
[Abstract]  GTPases are molecular switches that cycle between the inactive GDP-bound state and the active GTP-bound state. GTPases exchange nucleotides either by its intrinsic nucleotide exchange or by interaction with guanine nucleotide exchange factors (GEFs). Monitoring the nucleotide exchange in vitro, together with reconstitution of direct interactions with regulatory proteins, provides key insights into how a GTPase is activated. In this protocol, we describe core methods to monitor nucleotide exchange using fluorescent N-Methylanthraniloyl (MANT)-guanine nucleotide. [摘要]  GTP酶是分子开关,在无效GDP结合状态和活性GTP结合状态之间循环。 GTP酶通过其内在的核苷酸交换或通过与鸟嘌呤核苷酸交换因子(GEF)的相互作用来交换核苷酸。 监测体外核苷酸交换,以及与调节蛋白直接相互作用的重构,为GTP酶如何被激活提供了重要见解。 在该协议中,我们描述了使用荧光N-甲基呋喃酰基(MANT) - 鸟嘌呤核苷酸来监测核苷酸交换的核心方法。

【背景】GTPase是鸟嘌呤核苷酸结合蛋白,调节细胞过程的广度,从蛋白质生物合成到细胞周期进展,从细胞骨架重组到膜运输。 GTPases可以被认为是分子开关,它在GDP结合“关闭”状态和GTP结合“开启”状态之间循环;在通过GTP的GDP核苷酸交换结合GTP时,GTP酶变得活跃并且将结合下游效应蛋白以招募和激活这些效应子的生物学功能。 GTP酶通过与开关I环(G2结构域)的高度保守苏氨酸和开关II环(G3结构域)的DxxG基序内的甘氨酸的相互作用结合GTP的γ-磷酸。 GTP水解后,与γ-磷酸相互作用的丧失导致动态构象变化,从而使GTPase变为关闭状态(Vetter and ...

Proteasome Assay in Cell Lysates
Author:
Date:
2014-01-20
[Abstract]  The ubiquitin-proteasome system (UPS) mediates the majority of the proteolysis seen in the cytoplasm and nucleus of mammalian cells. As such it plays an important role in the regulation of a variety of physiological and pathophysiological processes including tumorigenesis, inflammation and cell death (Ciechanover, 2005; Kisselev and Goldberg, 2001). A number of recent studies have shown that proteasome activity is decreased in a variety of neurological disorders including Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis and stroke as well as during normal aging (Chung et al., 2001; Ciechanover and Brundin, 2003; Betarbet et al., 2005). This decrease in proteasome activity is thought to play a critical role in the accumulation of abnormal and ... [摘要]  泛素 - 蛋白酶体系统(UPS)介导哺乳动物细胞的细胞质和细胞核中大部分蛋白水解。因此,它在调节各种生理和病理生理过程中起重要作用,包括肿瘤发生,炎症和细胞死亡(Ciechanover,2005; Kisselev和Goldberg,2001)。许多最近的研究表明,在多种神经障碍(包括帕金森病,阿尔茨海默病,肌萎缩性侧索硬化和中风)以及正常衰老期间,蛋白酶体活性降低(Chung等,2001; Ciechanover和Brundin,2003; Betarbet等,2005)。蛋白酶体活性的降低被认为在异常和氧化蛋白质的积累中发挥关键作用。 UPS的蛋白质清除涉及两个连续的反应。第一个是用泛素(Ub)标记蛋白质赖氨酸残基,第二个是蛋白酶体随后降解标记的蛋白质。我们本文描述了这两个反应中第二个的测定(Valera等,2013)。该测定法使用荧光底物作为蛋白酶体的三种活性:糜蛋白酶样活性,胰蛋白酶样活性和半胱天冬酶样活性。通过蛋白酶体从底物中切割荧光团可导致可用荧光板读数器检测的荧光。

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