基于表面等离子体共振技术的血清白蛋白与色氨酸对映异构体手性识别的热力学研究

利用表面等离子体共振(SPR)技术,从热力学角度研究了牛血清白蛋白、人血清白蛋白与色氨酸对映异构体相互作用的手性识别,考察了p H值、离子强度和温度对亲和力的影响.利用热力学方法计算并探讨了作用机理.实验结果表明,牛血清白蛋白及人血清白蛋白与L-色氨酸的结合有高度特异性.热力学参数计算结果证明疏水作用在手性识别过程中起主要作用,但不排除静电作用有一定的贡献.     

Electrochemical Determination of Uric Acid,Dopamine and Tryptophan at Zinc Hexacyanoferrate Clay Modified Electrode

A Cameroonian smectite clay has been transformed into Zn²⁺ homoionic form and then used to prepare film modified glassy carbon electrodes and carbon paste electrodes. These electrodes containing Zn²⁺ were exploited to prepare a mixed valence zinc hexacyanoferrate (ZnHCF). Cyclic voltammetry has been employed to monitor the in situ growth of ZnHCF on clay modified electrodes. Although interesting electrocatalytic properties toward UA were observed with these modified electrodes, the modified carbon paste electrodes were the most suitable for dopamine, uric acid and tryptophan detection and exhibited for these analytes extended linear range, high sensitivities, selectivity and low limit.     

A Highly Sensitive Sensor Based on Reduced Graphene Oxide,Carbon Nanotube and a Co(II) Complex Modified Carbon Paste Electrode: Simultaneous Determination of Isoprenaline,Captopril and Tryptophan

This paper describes the development of a reduced graphene oxide (RGO), carbon nanotube (CNT) and Co(II) complex (cobalt(II) bis (benzoylacetone) ethylenediimino) (CBE) modified carbon paste electrode (CPE) for simultaneous determination of isoprenaline (IP), captopril (CAP) and tryptophan (Try). A pair of well‐defined redox peaks of Co(II) complex were obtained through a direct electron transfer between the Co(II) complex and the CPE. The proposed sensor showed very efficient electrocatalytic activity for anodic oxidation of IP in a 0.1 M phosphate buffer solution (pH 7.0). Square wave voltammetry (SWV) exhibited two linear dynamic ranges of 0.125–30.0 µM and 30.0–300.0 µM for IP. The detection limit for IP was found to be 50 nM. The proposed sensor was successfully applied for the determination of IP in real samples such as human blood serum, urine and IP ampoule.     

菊粉酶中色氨酸残基的化学修饰及其荧光光谱

用N-溴代琥珀酰亚胺为修饰剂, 研究菊粉酶中的Trp残基的分布及其对酶生物学功能的影响, 为进一步研究菊粉酶结构与其功能之间的关系提供了新的信息.     

环糊精超分子体系的手性识别研究──D,L-色氨酸对映体的手性识别荧光分析法

超分子体系的分子识别,甚至手性识别特征对从分子水平上模拟生物功能,研究生物体内各种信息的传递及酶与底物相结合过程等具有重要的理论和实际意义,它的应用也为发展特异性、专一性、选择性高的分析方法提供了广阔的前景[1,2]．环糊精是不同个数的吡哺型葡萄糖单元通过a－1,4糖音键联接而成的筒状低聚糖,其手性内腔早已引起人们的注意,并成功地应用在对映体化合物的色谱手性拆分、模拟酶反应和选择性催化反应等领域［3］．本文研究首次发现D,L-色氨酸对映体在外环糊精存在下呈现显著不同的手性包络差异,这种差异与酸度和温度密切…     

超分子体系中的分子识别研究(一)——有机硒修饰β-环糊精的合成及其与L-和D-色氨酸的包结配位作用

我们曾报道了天然环糊精及一些化学修饰环糊精对氨基酸生物小分子的识别研究 [1～ 3] ,结果表明 ,多种弱相互作用协同贡献于环糊精 -氨基酸超分子配合物的形成 ,修饰环糊精取代基的形状及尺寸影响对氨基酸的分子识别和手性识别能力 .本文通过亲核取代反应将芳香有机硒基团引入到β-环糊精的 2 -位 (化学结构如下式 ) ,荧光光谱滴定法研究结果表明 ,疏水性取代基的引入扩展了环糊精的分子键合能力 ,但手性识别能力降低 .1　实验部分1 .1　仪器及试剂　荧光光谱采用 JASCO FP- 750荧光光谱仪 ,普通 1 0 mm× 1 0 mm× 40 mm石英样品池 ,在 …     

稀土金属离子与色氨酸相互作用的荧光光谱研究

在碱性介质中,稀土离子与色氨酸形成离子缔合型异配位络合物使色氨酸的荧光猝灭,在pH=10-11的H3BO4－HAc-H3PO4-NaOH介质中,色氨酸的荧光发射和稀土离子对其荧光猝灭均达到最大值,各个稀土离子对色氨酸的荧光猝灭强度也基本相似,本文还建立了稀土离子与色氨酸配合物的分子模型并对其荧光猝灭机理进行了探讨。     

短小芽孢杆菌碱性蛋白酶的结构研究

测定了短小芽孢杆菌碱性蛋白酶BP的分子量为19 500,分析了它的氨基酸组成。用N-溴代琥珀酰亚胺对酶进行了化学修饰,以紫外光谱法测得此酶含有2个色氨酸残基,其中一个残基为酶表现活性的必需基团,且位于分子表面。用荧光表面猝灭剂法推测另一个残基也位于分子表面或临近分子表面。通过其园二色谱证明此酶为无规则卷曲构象。     

Tryptophanbestimmung im Gehirn Spezifische fluorimetrische Methode in Gegenwart von Analoga und Metaboliten

Zusammenfassung Es wurde eine Methode zur Bestimmung von Tryptophan in Gehirn ausgearbeitet. Diese führt in Gegenwart von Formaldehyd und Salpetersäure zu einem Fluorophor (Typ Norharman), der — im Gegensatz zu ähnlichen Formaldehydreaktionen mit HCl u. a. — nur von Tryptamin schwach gestört wird. Serotonin, 5-Hydroxytryptophan, Xanthurensäure, 3Hydroxyanthranilsäure und 5-Hydroxyindolessigsäure stören die fluorimetrische Bestimmung (374/450 nm) nicht. Es kann sogar auf vorherige DC-Trennung verzichtet werden. Geschlechts- und altersspezifische Unterschiede des Tryptophangehalts im Rattenhirn sind nicht stark ausgeprägt.

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Determination of tryptophan in the brain. specific fluorimetric method in presence of analogues and metabolites

Summary A method for the determination of tryptophan in the brain was developed, which is based on the formation of a fluorophore (374/450 nm) in the presence of formaldehyde and nitric acid. In contrast to similar methods which use formaldehyde and hydrochloric acid, tryptamine interferes only weakly. Serotonin, 5-hydroxytryptophan, xanthurenic acid, 3-hydroxyanthranilic acid and 5-hydroxyindoleacetic acid do not interfere, t.l.c. separation prior to fluorophore formation can be omitted. Influence of sex and age on the tryptophan content in rat brain are not very marked.