胶束溶液中某些氨基酸和二肽的解离常数

用pH电位法测定了在SDS(十二烷基磺酸钠)胶束溶液中甘氨酰丙氨酸和六种氨基酸(甘氨酸、丙氨酸、缬氨酸、亮氨酸、异亮氨酸、苯丙氨酸)的两级酸解离常数 pKa1 和 pKa2,发现与水溶液相比 ,pKa 值均显著增加 ,即SDS胶束形成强烈抑制质子解离.结合1HNMR测定结果 ,讨论了pKa1和 pKa2 随SDS浓度的变化规律以及与各配体自身结构的关系     

N-(1-萘基)氨基乙酸的激发态分子内电荷转移和电子转移

氨基酸是蛋白质的基本结构单位 ,水溶液中基态氨基酸分子以内盐形式存在 [1] .由于质子化氨基的正诱导效应 ,羧基的离解常数显著提高 ,如氨基乙酸的羧基离解常数 ( 4.57× 1 0 -3mol/L,2 5℃ [1] )是乙酸 ( 1 .74× 1 0 -5 mol/L[2 ] )的 2 63倍 ;同时内盐结构亦使氨基酸和肽链具有分子内电偶极 ,后者已在肽链上电荷转移过程的调控中发挥重要作用 [3,4] .激发态氨基酸或肽的诱导效应和电偶极性质的研究尚未见报道 ,其主要原因可能是难有合适的激发方式和研究方法 .然而相关研究应予重视 ,因为研究结果将可能为生物酶活性的调节提供一种新的…     

革质红菇营养成分分析

对革质红菇中的氨基酸、灰分、粗蛋白、粗脂肪、粗纤维等进行了测定。结果表明,革质红菇中含有17种氨基酸,氨基酸总含量为26.53％。而且含有Zn、Fe、Si、Cu、Mn、Ni、Cr等7种人体所必需的矿物质。粗蛋白、粗脂肪、粗纤维、灰分、碳水化合物的含量分别为28.17%、3.90％、10.21%、8.45%、48.73%。     

Chemically-bonded chiral column packings for high-performance liquid chromatography

Summary N-Protected aminoacids have been chemically bonded to aminopropylated silica gel, and the resulting chiral phases have been applied to the LG resolution of racemic mixtures of polar compounds. Best results were obtained with surfacebound N-formyl-isoleucine and N-formylvaline, with which baseline resolutions of a range of aminoacid and aminoalcohol derivatives were achieved.Presented at the 14th International Symposium on Chromatography London, September, 1982     

芳二醛缩氨基酸Schif碱双核配合物的合成及表征(Ⅰ)

合成了两类芳二醛甘氨酸Ｓｃｈｉｆ碱配体及其Ｃｕ（Ⅱ）、Ｚｎ（Ⅱ）、Ｎｉ（Ⅱ）、Ｃｄ（Ⅱ）双核配合物，并对八种配合物进行了元素分析、红外光谱分析、差热热重分析、紫外可见光谱分析，确证了这些配合物的结构．     

Synthesis of a (+)-anatoxin-a analogue for monoclonal antibodies production

Anatoxin-a analogue was prepared by resolution of aminoacid 1 using chiral (R)-4-phenyl-oxazolidin-2-thione as derivatizing agent. X-ray diffraction of a diastereomer allowed us to determine its absolute configuration. The synthesis could then be completed in few steps followed by introduction of an amide linker bearing a terminal alkyne in order to attach a carrier protein for monoclonal antibodies production.     

d- and l-Serine, useful synthons for the synthesis of 24-hydroxyvitamin D3 metabolites. A formal synthesis of 1α,24R,25-(OH)3-D3, 24R,25-(OH)2-D3 and 24S,25-(OH)2-D3

d- and l-Serine have been used for the enantioselective synthesis of tosylates 7a and 7b, useful building blocks for the synthesis of triols 5a and 5b which have already been obtained via a diastereoselective synthesis and used for the synthesis of 2a, 2b and 2c. We have thus performed a formal synthesis of 24S,25-(OH)₂-D₃, 24R,25-(OH)₂-D₃ and 1α,24R,25-(OH)₃-D₃.     

The role of the mobile phase in the resolution of racemic esters of aminoacids by normal phase high-performance liquid chromatography

Summary The work in this paper demonstrates the effect of the mobile phase composition on interactions involving racemic esters of aminoacids and a chiral stationary phase derived from N-formylisoleucine. Aprotic solvents have been employed to test the resolution of these racemates. An increase in the alcohol concentration of the mobile phase results in the deterioration of selectivity. These solvents seem to favour high separation factors. The solvent 1,1,2-trichlorotri fluoroethane is a suitable mobile phase modifier for normal phase liquid chromatographic resolution of enantiomers of aminoacid esters.     

聚合物支载的有机催化剂Ⅱ.手性有机催化剂

对二十余年来聚合物支载的有机催化剂的合成、性能及其在催化反应中的应用,包括负载催化剂的回收和重复使用等进行了综述。用于支载体的聚合物包括交联聚合物、线型聚合物及树形聚合物;支载的有机催化剂包括手性及非手性催化剂两类。本文作为第二部分将介绍聚合物支载的手性有机催化剂,重点介绍近年来颇受重视的氨基酸及多肽类有机催化剂的研究及其应用进展。