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21.
Alexander Leitner 《Analytica chimica acta》2005,528(2):165-173
The presence of arginine as the naturally occurring amino acid with the highest gas-phase basicity strongly influences the fragmentation behavior of peptides undergoing collision-induced dissociation. Using a derivatization procedure recently developed in our group, based on a reversible reaction of the guanidino group with 2,3-butanedione and an arylboronic acid, we examined how this label affects the fragmentation patterns of labeled versus unlabeled peptides in MS/MS experiments. As part of this fundamental study, two groups of model peptides (angiotensins and bradykinins) as well as tryptic peptides were labeled according to our protocol and subjected to collision-induced dissociation (CID) in both a triple quadrupole and a quadrupole ion trap instrument. It was found that for angiotensins containing an AspArg sequence, C-terminal cleavage at Asp that occurs for native peptides was completely inhibited in Arg-labeled peptides. For bradykinins and peptides obtained from tryptic digests of standard proteins, some sample peptides were little affected by the tagging of arginine residues. Others, in contrast, exhibited an almost total loss of nonspecific backbone cleavage and their fragment ion spectra were dominated by loss of the arginine tag. These and other experimental results are discussed in view of the nature of the arginine tag and the concept of proton mobility. 相似文献
22.
Snežana S. Mitić Gordana Ž. Miletić Aleksandra N. Pavlović Snežana B. Tošić Dragan S. Velimirović 《中国化学会会志》2007,54(1):47-54
A kinetic method for the determination of micro quantities of amino acid arginine (Arg) is described in this paper. The catalytic activity of cobalt in the reaction of oxidation of purpurin (1,2,4‐trihydroxy‐antraquinone, PP) by hydrogen peroxide in alkaline buffer solution decreases in the presence of micro quantities of arginine, because of the formation of the complex. Operating conditions for the successful determination of arginine were optimized. The optimized conditions yielded a theoretical detection limit of 1.45 μg mL?1. Kinetic equations are proposed for the investigated process. The interference effects of certain foreign ions and amino acids upon the reaction rate were studied and removed in order to assess the selectivity of the method. The developed procedure was successfully applied to the determination of arginine in various pharmaceutical samples. The typical feature of this procedure is that determination can be carried out at room temperature and in a short analysis time. The newly developed method is simple, inexpensive and efficient for use in the analysis of a large number of samples. 相似文献
23.
The performance of the contactless conductivity (C4D) and diode array photometric (DAD) detectors has been compared for CE separations of creatinine, arginine and 3‐methylhistidine in acetic acid background electrolytes. The contactless conductivity detector response has also been modeled. It has been found that the two detectors provide similar responses and can readily be used for dual CE detection. Changes in the acetic acid concentration affect the C4D noise less than the DAD noise, but their effect on the C4D response to the analytes is greater than with DAD. In general, C4D provides better detection results at higher acetic acid concentrations, while DAD is more sensitive and reliable at very low ones. Capillaries with greater internal diameters are preferable for both detectors, provided that the separation efficiency is not adversely affected. Acetic acid is a suitable background electrolyte for CE separations of small, basic organic molecules. 相似文献
24.
Self-suspended Pure Polydiacetylene Nanoparticles with Selective Response to Lysine and Arginine 下载免费PDF全文
We demonstrate a very convenient access to self-suspended pure poly(10,12-pentacosadiynoic acid) (PDA) nanoparticles (NPs) simply by adding the ethanol solution of diacetylene monomer to water, followed by UV irradiation. The as-obtained PDA NPs are of high purity because no any initiator, catalyst or stabilizer was used during the whole process. The stabilizer-free PDA NPs are stable in the aqueous suspension. Due to the high purity and stability, the PDA NPs can respond sensitively and selectively to lysine and arginine among 18 kinds of water soluble natural amino acids; without the competitive interaction from the stabilizer, the sensitivity was enhanced. 相似文献
25.
盐酸精氨酸与四氯苯醌在硼砂溶液中 ,5 0℃下反应 1 2 0 min可获得 1∶ 1稳定的电荷转移络合物 ,其λmax=35 0 nm,表观摩尔吸光系数 ε=2 .2 6× 1 0 4L·mol-1 · cm-1 ,线性范围为 0— 1 0 μg/m L。测定了盐酸精氨酸注射液的含量 ,结果与文献方法一致 ,回收率在 1 0 0 .0 %— 1 0 0 .3%之间 ,相对标准偏差小于 0 .70 %。 相似文献
26.
A series of Nα-methyl-alkyl-l-arginine (Arg) analogues have been synthesized from inexpensive, commercially available starting materials. These analogues, once incorporated into pharmaceutically relevant peptides, are expected to increase binding affinity, receptor selectivity, lipophilicity, and stability as demonstrated with analogues of similar design and structure. 相似文献
27.
在0.2mol/LNaOH-0.04mol/LH3PO4-0.02mol/L(NH4)2SO4-0.04mol/LCH3COOH溶液中,精氨酸(Arg)在苯甲醛存在下产生一灵敏的吸附波。实验证明电活性物质为α-苯亚甲基精氨酸,其电极反应机理是分子内α->C=N基团被还原为亚胺。用该吸附波可在1×10(-3)~2×10(-6)mol/L范围内分析蛋白质中的Arg。 相似文献
28.
甘草次酸是甘草的主要活性物质之一,具有抗炎、抗溃疡、抗病毒、防治肿瘤等多种药理活性[1-1]。本文利用精氨酸与甘草次酸成盐,一方面改善了甘草次酸在水中的溶解度,可提高其生物利用度;另一方面可降低血管痉挛的发生[3],从而提高用药安全性。本文主要报道该化合物的波谱学特征。1实验部分1.1甘草次酸精氨酸盐的合成在反应瓶中加入等物质量的18β-甘草次酸(0·95g)和L-精氨酸(0·35g),用80%乙醇75mL溶解,室温下搅拌反应2h,减压除溶剂并干燥,得白色疏松粉末状物,即为甘草次酸精氨酸盐(GA-Arg)。其熔点为184℃~186℃,结构如图1所示。图1甘草… 相似文献
29.
A simple and efficient protocol for the synthesis of new N-protected α-aminoalkylphosphonic diphenyl esters--aromatic analogues of arginine--is presented. The crucial, guanylating step was achieved using S-ethyl-N,N′-di(Boc)isothiourea in chloroform and in the presence of Et3N and HgCl2. Deprotection of the derivatives obtained was performed using trifluoroacetic acid in CH2Cl2 or hydrogenolysis over Pd/C. The products are potent inhibitors of trypsin. 相似文献
30.
Paglia G D'Apolito O Tricarico F Garofalo D Corso G 《Journal of separation science》2008,31(13):2424-2429
Asymmetric N(G),-N(G)-dimethylarginine (ADMA) increases in diseases such as renal failure, diabetes mellitus, and hypercholesterolemia. The feasibility and utility of a hydrophilic interaction chromatography (HILIC) method for the separation of free L-arginine (Arg), ADMA, and symmetric N(G),-N(G')-dimethylarginine (SDMA) on a typical silica column were explored and the impact of some experimental parameters on the chromatographic behavior of these analytes was investigated. The effect of water and TFA content in mobile phase and of column temperature was investigated during the development of a fast and simple HILIC-MS/MS method that might be suitable for the quantification of free Arg, ADMA, and SDMA in plasma for routine analysis. Our results show that a good compromise between efficiency and peak shape with acceptable retention and total chromatographic run time is achieved using an ACN/water (90:10) mobile phase with TFA% as additive ranging from 0.015 to 0.025% and column temperature ranging from 25 to 30 degrees C. 相似文献