L－色氨酸－H_2O_2－ClO~－－CTAB流动注射化学发光反应的研究

本文采用反相流动注射法研究了在阳离子表面活性剂ＣＴＡＢ存在下，Ｌ－色氨酸－Ｈ２Ｏ２－ＣｌＯ－体系的化学发光行为，对影响化学发光强度的诸因素和表面活性剂的增强作用进行了试验和探讨，建立了化学发光测定Ｌ－色氨酸的新方法。线性范围１．０×１０－８～８．０×１０－６ｍｏｌ·Ｌ－１，检测限为４．０×１０－９ｍｏｌ·Ｌ－１（Ｓ／Ｎ＝２）。对合成试样中三种浓度的Ｌ－色氨酸测定的回收率在９７％～１０６％之间，相对标准偏差小于４％。     

(R)-N-乙酰四氢噻唑-2-硫酮-4-羧酸的合成和量子化学研究

（R）－N－乙酰四氢噻唑－2－硫酮－4－羧酸在三乙胺存在下同乙酰氯反应得到光学活性产物（R）－N－乙酰四氢噻唑－2－硫酮－4－羧酸．用半经验的量子化学方法研究反应物及产物的电子结构和反应热焓．     

乙酰-DL-环己基甘氨酸的合成

以环己基溴为原料,在醇钠存在下,经过与丙二酸二乙酯发生烃化反应,再水解,酸化、脱羧制得环己基乙酸;后者再经溴化、氨解得到DL－环己基甘氨酸;最后在醋酐存在下发生乙酰化反应得到了环氧合酶－2（COX－2）抑制剂JTE－522的重要中间体乙酰－DL－环己基甘氨酸,目标产物结构经元素分析,IR和^1H NMR验证。     

土豆汁修饰碳糊电极测定色氨酸的研究

本提出了用于测定色氨酸的土豆汁修饰碳糊电极，该电极选择性好，能有效地消除酪氨酸的干扰，在ｐＨ＝７．４的ＮａＨ２ＰＯ４－ＮａＯＨ生理缓冲液中，电极响应与色氨酸在９．８×１０＾－６～９．８×１０＾－５ｍｏｌ／Ｌ的浓度范围内呈线性关系，最低检出限是１．５×１０＾－６ｍｏｌ／Ｌ．并详细讨论了电极抗干扰能力与测定条件的关系。用该电极测定了实际样品氨基酸注射液中色氨酸的含量，结果与标准值吻合。     

色氨酸荧光猝灭法测定人发稀土总量

研究了稀土元素对色氨酸的荧光猝灭效应，结果发现，在pH=11的HAc-H3BO3-H3PO4-NaOH缓冲溶液中，。各种稀土元素对色氨酸的荧光有猝灭效应，在此基础上建立了色氨酸荧光猝灭法测定稀土总量的分析新方法。稀土总量在0－50ug/25mL范围内，色氨酸荧光强度的差值与稀土总量呈现良好的线性关系，方法检出限为0．23ug/L；相对标准偏差为1．1％－2．9％；样品加标回收率为98．9％－101．2％，方法简便，灵敏度高，已用于人发样品中稀土总量测定。     

用Lin光寿命变化分析血中游离色氨酸

全血用三氯醋酸去蛋白的上清液中加入不同量色氨酸，测Ｌｉｎ光寿命，以加入色氨酸与Ｌｉｎ光寿命变化回归方程与应用推导的公式ｘ０＝（τｉ－ｂｘｉ）／ｂ，计算血中游离色氨酸为１１．１μｇ／ｍＬ。与文献报道的一致。     

用磷光寿命变化测定碘离子与磷光体反应动力学参数

利用Ｉ＾－促进系间窜越，加快发现过程，缩短磷光寿命的特点，研究Ｉ＾－量改变与色氨酸，色胺磷光寿命关系，分别为：τ＝３．９８ｅ＾－０．０６５８ｘ，与τ＝３．５ｅ＾－０．０８９９ｘ，应用静态分析，推导Ｓｔｅｒｎ－Ｖｏｌｍｅｒ式，计算平衡常数Ｋｓ与ｋｉ，分别为：０．１０９与０．２００ｍｍｏｌ；０．０２７与０．０５１ｓｍｍｏｌ＾－１。利用本法分析了酷氨酸，苯丙氨酸，Ｌ－色氨酸，牛血清白蛋白，葡糖苷酸酶。     

固体石蜡作粘合剂的纯碳糊电极的电化学活化及其应用于色氨酸的测定

研究了以固体石蜡作粘合剂的纯碳糊电极的电化学活主用于色氨酸直接测定的方法。活化后的电极对色氨酸的吸附能力大大增加，在ＨＡｃ－ＮａＣ溶液中，于＋０．３Ｖ富集后，于＝１．０１Ｖ出峰，用线扫伏安法测定时，二次微分溶电流，与色氨酸浓度在８－１０μｇ／Ｌ范围内成线性；检测限可达２μｇ／Ｌ；２倍的酪氨酸和其它氨基酸不干扰，用于氨基酸酸芭物样品和合成血清样品中色氨酸的测定，相对标准偏差小于２％。     

铈与L—色氨酸荧光反应的应用

色氨酸是人体中一种必需氨基酸,它在饮食中存在对于组织合成很重要,因此测定食品中色氨酸含量有一定的意义.以荧光法测定色氨酸已有文献报道.但利用Ce~(4 )的氧化性氧化色氨酸的反应尚无人研究.本文研究了色氨酸-Ce~(4 )体系,发现在酸性介质中,Ce~(4 )可将色氨酸氧化为强荧光性物质,以此为基础荧光定量分析色氨酸.1 试验部分1.1 主要试剂与仪器Ce~(4 )标准贮存液:1×10~(-2)mol·L~(-1)准确称取硫酸铈0.4043g于烧杯中,加少量水,浓H_2SO_4 1～2ml,转入100ml量瓶中,摇匀,冷却,定容至刻度.L-色氨酸贮存液:275mg·L~(-1)RF-540荧光光度计(日本岛津)1.2 试验方法在10ml比色管中依次加入Ce~(4 )标液2ml,一定量L-色氨酸溶液,H_2SO_4(0.05mol·L~(-1) 1.6ml摇匀,放置10min,测定其荧光强度,液池1cm,λ_(ex)=303nm,λ_(em)=350nm,同时做试剂空白.     

游离和膜固定化脂肪酶在双液相介质中催化二肽合成的研究

以N－乙酰－L－苯丙氨酸乙酯和L－亮氨酰胺、L－丙氨酰胺、L－苯丙氨酰胺 、L－缬氨酰胺等L－氨基酰胺为底物，以游离或膜固定化脂肪酶为催化剂，在水、 有机溶剂单相和水－有机相双相体系反应介质中，合成了N－乙酰－L－苯丙氨酰基 －L－亮氨酰胺、N－乙酰－L－苯丙氨酰基－L－丙氨酰胺、N－乙酰－L－苯丙氨酰 基－L－苯丙氨酰胺、N－乙酰－L－苯丙氨酰基－L－缬氨酰胺等二肽。研究证明， 由于反应和纯化的同步进行，二肽可以在双液相酶膜反应器中达到高纯度和高收率 合成。     

Quantitative determination of singlet oxygen generated by excited state aromatic amino acids, proteins, and immunoglobulins

Singlet oxygen quantum yields generated by excited state aromatic amino acids (tryptophan, tyrosine, phenylalanine), N-acetylated amino acids (N-acetyl-tryptophan, N-acetyl-tyrosine, N-acetyl-phenylalanine), and from selected proteins and immunoglobulins have been quantified by time-resolved phosphorescence measurements. A small, but significant, quantum yield found for proteins and immunoglobulins demonstrates that molecular oxygen can diffuse through the polypeptide matrix and can be sensitized by residues buried within the folds of protein structure.     

Concerted electron-proton transfer (EPT) in the oxidation of tryptophan with hydroxide as a base

Tryptophan is unique among the redox-active amino acids owing to its weakly acidic indolic proton (pK(a) ≈ 16) compared to the -O-H proton of tyrosine (pK(a) = 10.1) or the -S-H proton of cysteine (pK(a) = 8.2). Stopped-flow and electrochemical measurements have been used to explore the roles of proton-coupled electron transfer and concerted electron-proton transfer (EPT) in tryptophan oxidation. The results of these studies have revealed a role for OH(-) as a proton acceptor base in EPT oxidation of N-acetyl-tryptophan but not for other common bases. The reorganizational barrier for (N-acetyl-tryptophan)(+/?) self-exchange is also estimated.     

Influence of vibrational energy flow on isomerization of flexible molecules: incorporating non-Rice-Ramsperger-Kassel-Marcus kinetics in the simulation of dipeptide isomerization

The conformational isomerization of a dipeptide, N-acetyl-tryptophan methyl amide (NATMA), is studied computationally by including important dynamical corrections to Rice-Ramsperger-Kassel-Marcus (RRKM) theory for the transition rate between pairs of isomers. The dynamical corrections arise from incomplete or sluggish vibrational energy flow in the dipeptide, a property suggested by the mode-selective chemistry that has been observed by Dian et al. [J. Chem. Phys. 120, 133 (2004)]. We compute the extent and rate of vibrational energy flow in NATMA quantum mechanically using local random matrix theory, which we then use to correct the RRKM theory rates. The latter rates are then introduced into a master equation to study the population dynamics of the dipeptide. Incomplete or slow vibrational energy flow is found to enhance the conformational selectivity of NATMA over RRKM estimates.     

Simultaneous analysis of kynurenine and tryptophan in human plasma by capillary electrophoresis with UV detection

Plasma kynurenine (Kyn)/tryptophan ratio has been proposed as a useful marker for the monitoring activation of the cellular immune system. Here, we describe an easy capillary electrophoresis method with UV detection for the separation and detection of Kyn and tryptophan in human plasma using methltryptophan as internal standard. The plasma samples were simply treated with acentonitrile for the elimination of proteins, the supernatant was evaporated, and the dried sample was resuspended with water and directly injected on the capillary without sample derivatization procedures. The use of a run buffer composed by 100 mmol/L Bis-Tris propane at pH 2.15 allowed to baseline resolve the analytes within 9 min. Precision tests indicated a good repeatability of our method both for times (CV< 0.53%) and areas (CV< 2.8%). Moreover, a good reproducibility of intra-assay and interassay tests was obtained (CV < 3.9% and CV < 7.6%, respectively). The obtained limit of detections for Kyn and tryptophane, evaluated at 226 nm, were 0.15 and 0.40 μmol/L, respectively. The method suitability was tested by measuring analyte levels both in healthy volunteers, acute myocardial infarction and chronic kidney disease patients.     

L-色氨酸甲酯氢溴酸盐与醛的高立体选择性Pictet-Spengler反应合成手性1,3-二取代-1,2,3,4-四氢-β-咔啉

研究了L-色氨酸甲酯氢溴酸盐与醛的Pictet-Spengler反应,该反应经过一个晶体诱导过程,高立体选择性地合成了一系列1,3-二取代-1,2,3,4-四氢-β-咔啉化合物,其结构经~1H NMR,IR,MS和元素分析表征.     

Synthesis of Coumarin-functionalized Calix[4]arene and Selective Recognition for L-Tryptophan

We report a novel calixarene derivative using 4-bromomethyl-7-methoxycoumarin as the pre-organized unit and apply it to investigate selectively discriminate L-tryptophan from other amino acids in DMF-acetonitrile. 5, 11, 17, 23-Tetra-tert-butyl-25,27-bis-…     

Synthesis and Structure of a Two-dimensional Double Chain Iron(Ⅱ)L-Trp Coordination Polymer[Fe(L-trp)2(HL-trp)2]n

The title complex [Fe(L-trp)2(HL-trp)2]n(L-trp=L-tryptohan or 2-amino-3-(1H -indol-3-y1)-propanoic acid)has been formed by a hydrothermal method involving hexaaqua-cobaltous perchlorate and L-tryptophan.The product was characterized by elemental analysis,IR spectra and single-crystal X-ray diffraction.The crysal belongs to the monoclinic system,space group P21/c,with a=19.828(3),b=5.4233(14),c=9.2796(16)(A),β=97.691(2)°,V=988.9(3)(A)3,Z=2,Mr=462.29,Dx=1.553 g/cm3,F(000)=480,μ=0.802 mm-1,the final R=0.0399 and wR=0.0930 for 1738 observed reflections with I＞2o(I).The structural analysis shows that the complex assumes a two-dimensional double chain plane structure.     

盐酸吡哆辛在聚L-色氨酸修饰电极上的电化学行为及其分析测定

制备了聚L-色氨酸修饰玻碳电极(PTRP/GCE),用循环伏安法、线性单扫描伏安法、计时电量法等研究了盐酸吡哆辛(VB6)在PTRP/GCE上的电化学行为及电化学动力学性质, 实验表明：VB6在PTRP/GCE上的电极过程为1电子1质子的不可逆氧化反应,在20～400mV/s范围内,峰电流与扫速的平方根呈良好的线性关系,电极活化面积A为0.29cm2,扩散系数D为1.9612×10-4cm2/s。在pH=3的HAc-NaAc缓冲溶液中,VB6在PTRP/GCE电极上氧化峰电流与其浓度在1×10-4～5×10-6mol/L范围内呈良好的线性关系,线性回归方程为：ipa（μA） =7.7399+408.8129c (mmol/L),R=0.9931,检出限为1×10-6mol/L,VB6样品测定平均回收率为100.15%。     

高效液相色谱法测定氨基酸口服液中L-色氨酸的不确定度评定

采用高效液相色谱法测定氨基酸口服液中L-色氨酸的含量,对测量结果的不确定度进行评定。结果表明,标准曲线校准和测量重复性是测量过程中不确定度的主要来源,其中标准曲线校准对合成不确定度的影响最大。当氨基酸口服液中L-色氨酸的测定结果为8.8μg/mL时,其扩展不确定度为1.1μg/mL。