丙氨酰-谷氨酰胺的简便有效合成

谷氨酰胺 (Ｇｌｎ)是肠道必需氨基酸 ,是肠粘膜细胞氧化的重要燃料。肠粘膜缺乏Ｇｌｎ将严重损伤肠屏障功能 ,创伤性休克及化疗应激可加重损害 ,导致肠粘膜萎缩 ,肠道细菌移位 ,甚至促发脓毒症和多器官功能不全 (ＭＯＤＳ) [1] 。但Ｇｌｎ性质不稳定 ,不能耐高温消毒 ,因此 ,一般氨基酸制剂不含Ｇｌｎ。Ａｌａ Ｇｌｎ为Ｇｌｎ代谢前体 ,溶解度高 ,性质较Ｇｌｎ稳定 ,能耐受热灭菌 ,在体内数分钟即分解出Ｇｌｎ ,能部分补偿肠道所需Ｇｌｎ ,减少严重创伤及腹腔注射化疗药物 5 氟尿嘧啶 (5 ＦＵ)引发的小肠粘膜形态功能改变 ,细菌移位 ,降低…     

高效液相色谱荧光法快速检测人血浆及肌肉听谷氨酰胺

谷氨酰胺（ＧＬＮ）是肝脏糖异生的主要物质，同时又是肠粘膜细胞优先锋氧人，关许多代谢疾病中ＧＬＮ的需要量大大超出机体合成能力。导致血浆、肌细胞内ＧＬＮ浓度下降。ＧＬＮ蛋白质合成的减少、肠粘膜及免疫功能损伤有高度的相关性细胞内ＧＬＮ浓度的下降与病人的死亡率成正比。目前ＧＬＮ的测定多为酶法及全氨基酸谱分析法，这些方法在临床及研究中应用时既复杂费时，且成本较高。对此本文建立了一个快速简便灵敏的反相高效液相     

高效液相色谱荧光法快速检测人血浆及肌肉中的谷氨酰胺

谷氨酰胺（ＧＬＮ）是肝脏糖异生的主要物质,同时又是肠粘膜细胞优先利用的氧化原料,在许多代谢性疾病中ＧＬＮ的需要量大大超出机体合成能力,导致血浆、肌细胞内ＧＬＮ浓度下降。ＧＬＮ浓度的下降与蛋白质合成的减少、肠粘膜萎缩及免疫功能损伤有高度的相关性,细胞内ＧＬＮ浓度的下降与病人的死亡率成正比。目前ＧＬＮ的测定多为酶法及全氨基酸谱分析法,这些方法在临床及研究中应用时既复杂费时,且成本较高。对此本文建立了一个快速简便而灵敏的反相高效液相色谱法。     

柏子仁化学成分与药理活性研究进展

柏子仁(arboruitae seed),为柏科植物侧柏Platycladus orientalis(L.) Franco的干燥成熟种仁.在化学成分方面,柏子仁含有脂类、氨基酸、皂苷、萜类和多糖等有效成分,具有镇静安神、抗抑郁、减少小鼠自主活动次数、改善阿尔茨海默病、加强肠推进、治疗不孕症等作用.本文对柏子仁的化学成分、药理活性和临床应用等相关研究进行综述,以指导该药物的开发利用,并为临床合理应用提供可靠的参考.     

反相高效液相色谱法测定血清中的游离氨基酸

肝脏是氨基酸(支链氨基酸除外)新陈代谢的重要器官,而且对维持氨基酸代谢的平衡起重要的作用。当肝细胞严重损害时就会引起氨基酸代谢障碍和紊乱,使氨基酸之间比例失调,尤其明显地是支链氨基酸与芳香族氨基酸比值发生改变。根据该比值的改变情况既可预测肝性脑病,又可判断肝脏疾病的严重程度,而且氨基酸的测定对许多疾病的诊断及治疗均具有重要的价值,     

PTH-氨基酸的高压液相色谱分离

蛋白质和多肽是由各种氨基酸通过肽键相连而成,要阐明蛋白质的一级结构需先将其序列降解,然后测定依次降解出来的氨基酸。通常用Edman方法来降解蛋白质N-端氨基酸,使生成苯基海硫因氨基酸(简称PTH-氨基酸),而鉴定PTH-氨基酸常用的方法是气相色谱、薄层色谱和将降解生成的PTH-氨基酸再水解测定氨基酸的方法。近几年来,用高压液相色     

手性氨基酸及其衍生物配体在酮不对称氢转移反应中的应用进展

前手性酮的不对称氢转移反应(ATH)是获得手性醇的重要方法.近年来氨基酸及其衍生物在金属Ru,Rh,Ir催化酮的ATH中的应用引起人们关注.就氨基酸、氨基酸酰胺、氨基酸硫代酰胺、氨基酸羟胺酸、氨基酸酰肼、氨基醇及氨基酸羟基酰胺等为配体的金属络合物在ATH中的催化性能进行了综述.     

五氯化磷辅助下氨基酸的自组装成肽反应研究

L-α-氨基酸和D-α-氨基酸可与五氯化磷直接发生磷酰化反应，随后自组装成多肽，但β-氨基酸不能成肽，DL-α-氨基酸成肽困难；在SOCl2存在下，α-氨基酸也不能成肽，用电喷雾质谱研究了氨基酸的自组装反应，反应过程中有五元环状的氨基酸五配位磷中间体生成，使用硅烷基保护的氨基酸，在^31PNMR中可观察到五配位磷中间体。     

五氯化磷辅助下氨基酸的自组装成肽反应研究

L-α-氨基酸和D-α-氨基酸可与五氯化磷直接发生磷酰化反应，随后自组装成多肽，但β-氨基酸不能成肽，DL-α-氨基酸成肽困难；在SOCl2存在下，α-氨基酸也不能成肽，用电喷雾质谱研究了氨基酸的自组装反应，反应过程中有五元环状的氨基酸五配位磷中间体生成，使用硅烷基保护的氨基酸，在^31PNMR中可观察到五配位磷中间体。     

氨基酸在水/DMF混合溶剂中的焓相互作用

氨基酸是组成蛋白质的基本结构单位。溶质－溶质相互作用是氨基酸溶液热力学性质研究的一个主要方面，氨基酸的稀释焓是与之相应的一个重要热力学性质。目前，研究多集中在水溶液中，研究表明具有非极性侧链氨基酸和具有极性侧链氨基酸的偏摩尔焓是完全不同的，随着氨基酸...     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.