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Quartz cuvette Ultra-Micro cells

Company: Hellma
Catalog#: 105-201-15-40
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Microtubule Seeded-assembly in the Presence of Poorly Nucleating Nucleotide Analogues
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Date:
2020-08-20
[Abstract]  Microtubule dynamic instability is driven by the hydrolysis of the GTP bound to the β-subunit of the α-β tubulin heterodimer. Nucleotide analogues are commonly used to mimic the different steps of the tubulin GTPase cycle, but most of them are poor microtubule nucleators. Usually, microtubule assembly is seeded by guanylyl-(α, β)-methylene-diphosphonate (GMPCPP) or glycerol that can be limiting factors in monitoring the effect of other nucleotide analogs on their polymerization. Here, we describe a protocol that allows the assembly of microtubules in the presence of nucleotide analogues without the need of heterogeneous seeds and at a low final glycerol concentration. Microtubules are first assembled in the presence of the analogue of interest and glycerol to promote assembly. These ... [摘要]  [摘要 ] 微管动态不稳定性是由与α - β 微管蛋白异二聚体的β- 亚基结合的GTP水解驱动的。核苷酸类似物通常用于模拟微管蛋白GTPase循环的不同步骤,但其中大多数是不良的微管成核剂。通常,微管组装是通过胍基-(α ,β )-亚甲基-二膦酸酯(GMPCPP)或甘油来接种的,它们可能是限制其他核苷酸类似物对其聚合作用的监测因素。 在这里,我们描述了一种协议,该协议允许在核苷酸类似物存在的情况下组装微管,而无需异质种子,并且最终甘油浓度低。首先在感兴趣的类似物和甘油的存在下组装微管以促进组装。然后对这些微管进行超声处理,以产生种子,这些种子将在不存在甘油的情况下用于组装微管。这种策略产生了均质的核苷酸结合的微管,可以通过生化或结构方法(如冷冻电子显微镜)进一步分析。

[背景 ] 核苷酸类似物通常用于研究的构象变化,该α - β 微管组装和水解绑定到其可交换的(E)的网站上的GTP的期间微管蛋白异源二聚体经历。但是,除GMPCPP以外,大多数类似物都是微管成核剂。为克服这一困难,GMPCPP稳定化的种子通常用于存在其他类似物的情况下延长微管(Maurer 等人,2011和2014; Zhang ...

A Sensitive Coupled Enzyme Assay for Measuring Kinase and ATPase Kinetics Using ADP-Specific Hexokinase
Author:
Date:
2020-05-05
[Abstract]  Kinases and ATPases perform essential biological functions in metabolism and regulation. Activity of these enzymes is commonly measured by coupling ATP consumption to the synthesis of a detectable product. For most assay systems the ATP concentration during the reaction is unknown, compromising the precision of the assay.

Using the ADP-specific hexokinase (ADP-HK) from the thermophilic archaeon Thermococcus litoralis the protocol outlined here allows real time coupling of ATP consumption to downstream signal change enabling accurate kinetic measurements. ADP-HK phosphorylates glucose that is then used by glucose-6-phosphate dehydrogenase to reduce NAD+ to NADH which can be measured at 340 nm. We have shown this assay to be sensitive to the detection of ...
[摘要]  [摘要 ] 激酶和ATPase 在代谢和调节中起着至关重要的生物学功能。通常通过将ATP的消耗与可检测产物的合成耦合来测量这些酶的活性。对于大多数测定系统,反应过程中ATP的浓度是未知的,从而降低了精密度。分析方法。

使用ADP特定己糖激酶(ADP-HK)来自嗜热古菌嗜热litoralis的议定书概述这里可以进行实时耦合ATP消费对下行信号变化进行高精度动态测量。ADP-HK磷酸葡萄糖这随后被葡萄糖-6-磷酸脱氢酶可将NAD + 还原为NADH(可在340 nm处测定),已表明该测定法对检测ADP中的微摩尔量ADP敏感,没有可检测到ATP的背景。

[背景 ] 激酶和ATP酶可通过将ADP的产生与分光光度法可检测的信号偶联来测量。商业供应商提供了试剂盒,用于检测通过将ADP产生的或ATP消耗掉与荧光或生物发光信号的产生进行检测的试剂盒(例如ATP) - 格洛; Promega公司,ADP-传感器; Biovision所属..)这些套件敏感,但很难适用于动力学问题,因为他们是终点分析,测量ADP金额在单个时间点。此外,黑匣子自然这种试剂盒因此很难确定反应混合物是否处于Michaelis-Menten 动力学所需的稳态条件下。

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