二聚体[Ni(TSSB)(Phen)(H_2O)]·4H_2O的合成、表征、晶体结构及热分解研究

0引言含硫席夫碱及其金属配合物具有抑菌、抗癌和抗病毒的生物活性[1￣3],有些含O、N席夫碱金属配合物具有仿酶催化活性[4,5]。而氨基酸席夫碱配合物具有良好的生物生理活性,近年来得到人们的普遍重视[6,7],同α-氨基酸席夫碱相比,β-氨基酸席夫碱由于氨基位置的变化而引起不同     

牛磺酸缩3,5-二溴水杨醛席夫碱镁配合物[Mg(Br_2TSSB)(Phen)(H_2O)]·H_2O的合成及晶体结构

0引言含硫席夫碱及其金属配合物具有抑菌、抗癌和抗病毒的生物活性[1￣3],有些含O、N席夫碱金属配合物具有仿酶催化活性[4,5]。而氨基酸席夫碱配合物具有良好的生物生理活性,近年来得到人们的普遍重视[6,7]。同α-氨基酸席夫碱相比,β-氨基酸席夫碱由于氨基位置的变化而引起不同的配位特征,但研究此类席夫碱的报道目前还不多[8￣10]。2-氨基乙磺酸(牛磺酸)作为生物体内一种特殊的氨基酸,目前对它的研究主要集中在生理和病理方面,它的席夫碱及其配合物的研究或牛磺酸金属配合物的研究刚起步[2,10￣17]。研究表明,-SO32-可以与碱金属、碱土…     

4-氟苯甲醛丙氨酸席夫碱的合成及其IR和Raman光谱分析

席夫碱及其金属配合物具有杀菌、抗菌、植物生长调节等生理活性,在医药、农药等领域有广泛的应用前景[1-2].含氟席夫碱及其配合物具有独特的生物活性, 在医药研究中备受关注[3-4]; 氨基酸席夫碱一直是人们感兴趣的研究课题,但对含氟的氨基酸席夫碱的研究未见报道.本文报道了4-氟苯甲醛与丙氨酸形成的席夫碱的合成方法及利用1H NMR、红外光谱、拉曼光谱、热重分析等测试手段进行表征的结果,化合物的生物活性研究正在进行.     

双-[N(4-取代苯基)-水杨醛亚胺]合锌(Ⅱ)的晶体结构

为进一步研究过渡金属离子与席夫碱配合和的结构与性能的关系,本文报道双-[N-(4-取代苯基)-水杨醛亚胺]合锌的晶体结构.     

双-[N-(4-取代苯基)-水杨醛亚胺]合锌(Ⅱ)的晶体结构

许多过渡金属与席夫碱的配合物具有生物活性,研究这类化合物的晶体结构很重要,我们曾经报道了双—[N—4—取代苯基—水杨醛亚胺]含钴(Ⅱ)配合物的晶体结构,为了进一步研究过渡金属离子与席夫碱配合物结构与性能的关系,本文报道双—[N—(4—取代苯基)—水杨醛亚胺]合锌的晶体结构。     

两种席夫碱缓蚀剂对碳钢材料的缓蚀性能探究

采用了电化学方法研究了2种席夫碱缓蚀剂水杨醛基邻苯甲酸亚胺(SB-I)和N,N’-二水杨醛基-1,2-邻苯二亚胺(SB-II)在1 mol/L盐酸溶液中对20#碳钢的缓蚀性能。通过极化曲线和交流阻抗谱研究该席夫碱对碳钢的缓蚀效果表明:席夫碱对碳钢材料具有良好的缓蚀作用,其最大缓蚀率可达到83%。研究了席夫碱在碳钢表面的吸附模式,结果表明,席夫碱在碳钢表面上的吸附吉布斯自由能在-30 kJ/mol之间,表现为混合型缓蚀剂,即通过化学吸附和物理吸附之间的一种混合吸附在碳钢工作电极的表面,通过抑制、阻止延缓金属的电化学过程而起到缓蚀的作用。另外,实验还发现,SB-I比SB-II具有更好的缓蚀性能,该实验结果与理论计算结果相符合。     

牛磺酸缩邻香草醛席夫碱铜配合物[Cu(C_(12)H_8N_2)(C_(10)H_(11)NO_5S)]·3.5H_2O的合成及晶体结构

含硫席夫碱及其金属配合物具有抑菌、抗癌和抗病毒的生物活性[1-3],有些含O、N席夫碱金属配合物具有仿酶催化活性[4].而氨基酸席夫碱配合物具有良好的生理活性,近年来得到人们的普遍重视[5,6].2-氨基乙磺酸(牛磺酸)作为生物     

氨基酸席夫碱的合成及性质研究

合成了5种氨基酸席夫碱Sal-Gly(甘氨酸席夫碱)、Sal-Glu(谷氨酸席夫碱)、Sal-Met(甲硫氨酸席夫碱)、Sal-Tyr(酪氨酸席夫碱)、Sal-Arg(精氨酸席夫碱)及其金属锌离子配合物共10种化合物.用元素分析、核磁共振、红外光谱、紫外-可见光谱等手段对其组成的结构进行表征.以Sal-Tyr-Zn为主体,咪唑(1),1-甲基-咪唑(2),2-乙基-4-甲基咪唑(3),吡唑(4),4-碘苯胺(5),DABCO(1,4-重氮双环[2,2,2]辛烷)(6),邻苯二胺(7)和1,2-环己二胺(8)为客体,进行配位相互作用研究.选取大肠杆菌作为抑菌菌种,研究了氨基酸席夫碱的抑菌能力.结果表明,氨基酸席夫碱配体及金属锌配合物对大肠杆菌均有抑菌活性,配体的抗菌活性随氨基酸残基的增大而减小.金属锌配合物的抑菌活性大于其所对应的氨基酸席夫碱配体的抑菌活性,活性最大的则为Sal-Arg-Zn.     

水杨醛缩芳胺类席夫碱的光致变色性质

21世纪信息将主要以光为介质进行传输和处理,因此,需要开发出一系列的化合物或材料以用于高密度信息存储、电或光驱动的显示器件、光学运算以及其它非线性光学器件.水杨醛与芳胺衍生物缩合得到的水杨醛缩芳胺类席夫碱的生物活性和光学特性与其组成、结构、取向和分子间相互作用密切相关[1-2],具有光致变色或热致变色性质,受到人们的重视[3-5].因此,本文合成3种非两亲性的水杨醛席夫碱N-(对苯甲酸)-2-羟基苯甲亚胺(简称S1)、N-(对苯甲酸)-2-羟基-5-硝基苯甲亚胺(简称S2)和N-(对苯甲酸)-2-羟基-5-氯苯甲亚胺(简称S3),用紫外-可见光谱分别对其在不同溶剂中进行了光谱性质的研究,结果表明3种水杨醛缩芳胺席夫碱在不同溶剂中均具有光致变色性,其固态具有热致变色性,对光的宏观响应速度较快,为可能实用化提供了参考.     

三种邻香兰素还原型席夫碱-镍（Ⅱ）配合物的合成及表征

席夫(Schiff)碱可作为合成螯合物、生物活性剂、分子试剂和催化剂等的中间体[1,2].目前,对还原型席夫碱化合物的研究主要集中在水杨醛类还原型席夫碱,用邻香兰素与氨基酸合成邻香兰素氨基酸还原型席夫碱化合物的研究国内外尚未见报导.     

氨基酸卟啉锌配合物对氨基酸酯的分子识别研究(英文)

用紫外可见吸收光谱滴定方法研究了一种新型的苏氨酸卟啉锌配合物(主体)对氨基酸酯(客体)的分子识别.这种锌卟啉可以与氨基酸酯形成 1:1和 1:2的两种加合物.氨基酸酯的氨基首先与氨基酸残基的羧基作用形成 1:1的加合物,然后与锌卟啉的中央锌原子配位形成 1:2的加合物,客体分子与主体分子上的氨基酸残基之间的排斥作用以及主客体之间的色散力作用是主体分子能识别客体分子的另外两种作用。     

Synthesis and antifungal activity of rhodopeptin analogues. 1. Modification of the east and south amino acid moieties

Structure-activity relationships of the east and south amino acid modified analogues of rhodopeptins, novel antifungal cyclic tetrapeptides isolated from Rhodococcus species Mer-N1033, have been investigated. It was observed that a basic amino acid moiety (lysine or ornithine) as the east amino acid and a hydrophobic and bulky neutral amino acid (i.e., gamma-methylleucine) as the south amino acid were indispensable structure motifs for antifungal activity of rhodopeptin analogues.     

Fmoc保护氨基酸与Wang树脂的缩合反应

研究了保护氨基酸、Wang 树脂取代度、树脂粒度、搅拌方式对Fmoc-氨基酸-Wang树脂连接效率的影响. 结果表明, 保护氨基酸分子量的大小会因产生不同的位阻而影响缩合反应的效率, 分子量越小缩合效率越高; Wang树脂的取代度较高时, 已缩合的氨基酸给后续保护氨基酸的缩合形成阻碍, 使缩合效率降低; 粒径较小和搅拌较好时, 对保护氨基酸的粒内外扩散有利, 可提高反应速度和缩合效率.     

Dual substrate recognition of aminotransferases

Pyridoxal 5'-phosphate-dependent aminotransferases reversibly catalyzes the transamination reaction in which the alpha-amino group of amino acid 1 is transferred to the 2-oxo acid of amino acid 2 (usually 2-oxoglutarate) to produce the 2-oxo acid of amino acid 1 and amino acid 2 (glutamate). An aminotransferase must thus be able to recognize and bind two kinds of amino acids (amino acids 1 and 2), the side chains of which are different in shape and properties, from among many other small molecules. The dual substrate recognition mechanism has been discovered based on three-dimensional structures of aromatic amino acids, histidinol phosphate, glutamine:phenylpyruvate, acetylornithine, and branched-chain amino acid aminotransferases. There are two representative strategies for dual substrate recognition. An aromatic amino acid aminotransferase prepares charged and neutral pockets for acidic and aromatic side chains, respectively, at the same place by a large-scale rearrangement of the hydrogen-bond network caused by the induced fit. In a branched-chain aminotransferase, the same hydrophobic cavity implanted with hydrophilic sites accommodates both hydrophobic and acidic side chains without side-chain rearrangements of the active-site residues, which is reminiscent of the lock and key mechanism. Dual substrate recognition in other aminotransferases is attained by combining the two representative methods.     

R(-)四氢噻唑-2-硫酮-4-羧酸对D,L-氨基酸酯拆分的研究

以新手性拆分试剂R(-)四氢噻唑-2-硫酮-4-羧酸[简称R(-)TTCA]对D,L-氨基酸酯进行手性拆分,分别得到(R)TTCA氨基酸酯盐1a_1f([α]_D²⁰＝-30.40°～-42.70°)及光学活性氨基酸酯2a-2f,其光学纯度为35.4%～75.8%.由1a_1f在碱存在下分解出2a-2f的对映体3a-3f,光学纯度为39.50%～69.10%.用半经验的量子化学PM3方法研究了氨基的碱性、中间产物铵盐生成热和稳定性.     

Enantioselective synthesis of an unnatural bipyridyl amino acid and its incorporation into a peptide

The synthesis of a bipyridyl amino acid, 2-amino-3-(4′-methyl-2,2′-bipyridin-4-yl) propanoic acid, is described. A short three step synthesis from commercially available 4,4′-dimethyl-2,2′-bipyridine provides the amino acid in 65% enantiomeric excess (ee). An enzyme-mediated chiral resolution increases the ee to 95% in two additional steps. The amino acid was incorporated into a 22 amino acid peptide composed predominantly of alanine. The peptide was found to be 88% α-helical in aqueous solution at 1°C by circular dichroism (CD) spectropolarimetry, indicating a high helical propensity for this amino acid. This amino acid can provide a means to incorporate a metal into structure-forming peptides.     

The effect of hydrolysis time on amino acid analysis

Determining the amino acid content of a protein involves the hydrolysis of that protein, usually in acid, until the protein-bound amino acids are released and made available for detection. Both the variability in the ease of peptide bond cleavage and differences in the acid stability of certain amino acids can significantly affect determination of a protein's amino acid content. By using multiple hydrolysis intervals, a greater degree of accuracy can be obtained in amino acid analysis. Correction factors derived by linear extrapolation of serial hydrolysis data are currently used. Compartmental modeling of the simultaneous hydrolysis (yield) and degradation (decay) of amino acids by nonlinear multiple regression of serial hydrolysis data has also been validated and applied to determine the amino acid composition of various biological samples, including egg-white lysozyme, human milk protein, and hair. Implicit in the routine application of serial hydrolysis in amino acid analysis, however, is an understanding that correction factors, derived either linearly or through the more accurate nonlinear multiple regression approach, need to be determined for individual proteins rather than be applied uniformly across all protein types.     

INTERACTION OF AMINO ACID WITH ION EXCHANGE RESIN Ⅲ.FURTHER INVESTIGA TION OF SUPEREQUIVALENT ADSORPTION MECHANISM OF AMINO ACID ON ION EXCHANGE RESIN

The adsorption isotherms of glycine,alanine and oxidized glutathion on strong acid cation and strong base anion exchange resins from aqueous solutions were measured and the superequivalent adsorptions of glycine and alanine observed.The infrared spectra of glycine adsorbed on the cation and the anion exchange resins,001×7 and 201×7,were measured.From these results,it is concluded that the amino acid adsorption on the ion exchange resin proceeds not only through ion exchange and proton transfer mechanisms,but also through aminecarboxylate interaction between the adsorbed amino acid molecules,and the formation of second layer of amino acid molecules is the mechanism of superequivalent adsorption of amino acid,the carboxylate or amine groups of the first layer of amino acid molecules on the ion exchange resin act as the exchange sites for the second layer of amino acid molecules.     

Adsorption behavior of urokinase by polypropylene film modified with amino acids as affinity groups

In order to prepare a new-type adsorbent with an affinity ligand, polypropylene films modified with amino acid groups such as -phenylalanine (Phe), , -Phe, -cysteine (Cys), and , -tryptophane (Try), were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) films and subsequent amination of poly-GMA graft chains. The physical and chemical properties of the GMA-grafted PP film and the PP film modified with amino acid groups were investigated by IR and XPS. The adsorption of urokinase for the PP films modified with four kinds of amino acid groups were examined under various conditions, such as the contents of the amino acid group and pH value. The adsorption of urokinase increased with the increasing content of the amino acid group. The adsorption of the PP film modified with four kinds of amino acid groups was in the following order: -Phe> , -Phe> , -Try> -Cys. The adsorption amounts of urokinase by the PP film modified with four kinds of amino acid groups at pH 7.4 was higher than that at pH 9.0.     

Comprehensive Evaluation of Amino Acids and Polyphenols in 69 Varieties of Green Cabbage (Brassica oleracea L. var. capitata L.) Based on Multivariate Statistical Analysis

The biological activities of the primary metabolites and secondary metabolites of 69 green cabbage varieties were tested. The LC-MS detection method was used to determine the content of 19 free amino acids (lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, arginine, asparagine, glycine, proline, tyrosine, glutamine, alanine, aspartic acid, serine, and glutamate). The content of 10 polyphenols (chlorogenic acid, gallic acid, 4-coumaric acid, ferulic acid, gentisic acid, cymarin, erucic acid, benzoic acid, rutin, and kaempferol) was determined by the HPLC detection method. Considering the complexity of the data obtained, variance analysis, diversity analysis, correlation analysis, hierarchical cluster analysis (HCA), and principal component analysis (PCA) were used to process and correlate amino acid or polyphenol data, respectively. The results showed that there were significant differences between the different amino acids and polyphenols of the 69 cabbage varieties. The most abundant amino acids and polyphenols were Glu and rutin, respectively. Both amino acids and polyphenols had a high genetic diversity, and multiple groups of significant or extremely significant correlations. The 69 cabbage varieties were divided into two groups, according to 19 amino acid indexes, by PCA. Among them, seven varieties with high amino acid content all fell into the fourth quadrant. The HCA of amino acids also supports this view. Based on 10 polyphenols, the 69 cabbage varieties were divided into two groups by HCA. Based on 29 indexes of amino acids and polyphenols, 69 cabbage varieties were evaluated and ranked by PCA. Therefore, in this study, cabbage varieties were classified in accordance with the level of amino acids and polyphenols, which provided a theoretical basis for the genetic improvement of nutritional quality in cabbage.