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链霉菌M1033葡萄糖异构酶的分离纯化及其性质的研究 总被引:7,自引:0,他引:7
链霉菌M1033菌株所产的葡萄糖异构酶培养液经二级(NH_4)_2SO_4沉淀、DEAE-Sephadex A50,Sephadex-G150柱层析分离纯化,可得到电泳均一的纯酶。该酶的全分子量为91000左右,由两个相同的亚基组成。其pI为4.3,经糖染色后证明并非糖蛋白;最适反应温度70℃,在该温度下分别以D-木糖和D-葡萄糖为底物,测得最适pH分别为8.0和8.3。该酶为金属激活酶。Co~(2 )和Mg~(2 )对该酶有激活作用,Ca~(2 )则使之几乎失活。金属离子的激活作用随底物而异。动力学研究表明,该酶对D-木糖有更大的亲和性。 相似文献
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矿区活动断裂空间形态EH4探测 总被引:1,自引:0,他引:1
为了查明地质动力区划确定的活动断裂的存在与地下分布状态对煤与瓦斯突出的影响,利用质动力区划方法对鹤岗兴安井田区域内活动断裂进行划分,建立了板块构造学和矿井工程实际的联系。通过野外考察选取了对兴安矿煤与瓦斯突出影响严重的Ⅲ-1和Ⅳ-3活动断裂为研究对象,进行EH4电导率剖面测量,最终确定了两条活动断裂的空间分布状态。研究表明活动断裂控制着煤与瓦斯突出的区域性分布,EH4活动断裂电导率测量提供了活动构造探测新方法,对矿井动力灾害危险性预测和井下开采具有指导意义,可以在矿井实际工程中应用推广。 相似文献
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Non-enzymatic biosensors based on various nanomaterials with large surface-volume ratios and high catalytic efficiencies have been proposed to compensate for the non-stability and high cost of enzymatic biosensors. However, the construction of a stable, highly sensitive, flexible, three-dimensional (3D), microstructured, non-enzymatic biosensor integrated with a smartphone-based portable system has been challenging. Herein, highly conductive laser-induced graphene (LIG) array with a honeycomb-like 3D microstructure co-decorated with copper(I) oxide and gold nanocatalysts was developed via simple and green electro-deposition and chemical reduction approaches for a miniaturized electrochemical flexible non-enzymatic biosensor. SEM, XRD, Raman and XPS analyzations indicated that the Cu2O and Au nanocatalysts co-decorated three-dimensional, laser-induced graphene hybrid nanomaterials were developed successfully. The signal of the biosensor was improved by more than 10 fold compared to the LIG alone due to the co-decorated with copper(I) oxide and gold nanocatalysts. The fabricated electrochemical biochip was integrated with a smartphone-based microstation for glucose monitoring, presenting a larger linear interval of 1–20 mM with an excellent sensitivity of 236 μA/mM/cm2 and a relatively low detection limit of 0.31 μM. Noticeably, the biochip could measure blood sugar on curved surfaces and still deliver stable sensing signals after being bent back-and-forth 25 times. The novel biosensor is a potentially valuable flexible electronic device. The hybrid nanomaterials developed in this work may be applicable to other biosensing, catalytic, and energy devices (supercapacitors and batteries). 相似文献
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Xiaojuan Zhang Qian Zhang Yuzhen Wu Chao Feng Chao Xie Xiaodong Fan Pengfei Li 《Macromolecular rapid communications》2016,37(16):1311-1317
The azide–alkyne “click” reaction has been well known in the past decade, however, another kind of 1,3‐dipolar cycloaddition, the azide–alkene reaction is not fully explored in polymer science to date. This contribution reports, for the first time, the discovery of a polyaddition of norbornene based monomer (NC11N3) containing both strained double bond and azide moieties. The reaction product is characterized by Fourier transform infrared spectroscopy (FTIR), NMR, gel permeation chromatography (GPC), and mass spectrometry (MS), which confirmed the mechanism that is through cycloaddition of azide to strained double bond on norbornene ring to form triazoline linkage. The reaction can proceed at room temperature as indicated by the increase of molecular weight and viscosity during storage. Monomer, dimer, trimer, tetramer, etc., and species with loss of N2 due to lability of triazoline moiety are identified in the mixture of reaction product. As a unique feature, elimination of N2 in the five‐membered ring of triazoline affords a chance to form highly reactive materials, such as with aziridine, which can be a very powerful tool in chemical functionalizations, and find promising applications in reactive polymer resin industries.
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In this paper, we consider a model of nonlinear viscoelastic shallow shell that is referred to as the full Marguerre-von Kármán under the presence of long-time memory. We show that the energy functional associated with the system decays exponentially to zero as time goes to infinity. 相似文献