基于N-乙酰-L-半胱氨酸修饰的ZnFe2O4@SiO2纳米材料手性识别酪氨酸对映异构体

我们将N-乙酰-L-半胱氨酸（NALC）修饰于ZnFe₂O₄@SiO₂纳米材料表面,制备了一种新型的手性纳米复合物（ZnFe₂O₄@SiO₂-NALC）,该材料能够简便、快速及高选择性地识别手性酪氨酸（Tyr）对映体。利用X射线粉末衍射（XRD）、红外光谱（FT-IR）、能量色散X射线光谱（EDS）、扫描电子显微镜（SEM）、高分辨率透射电子显微镜（HRTEM）和振动样品磁力计（VSM）等一系列表征手段对首次合成出的ZnFe₂O₄@SiO₂-NALC进行测试表征,并将其应用于对手性识别领域的探究。实验结果表明,利用光谱技术（紫外-可见光谱和荧光光谱）,ZnFe₂O₄@SiO₂-NALC可对Tyr对映异构体进行手性识别。此外,我们进一步对Tyr浓度和pH值等实验参数进行了优化。     

Transformation of Receptor Tyrosine Kinases into Glutamate Receptors and Photoreceptors

Receptor tyrosine kinases (RTKs) are key regulators of cellular functions in metazoans. In vertebrates, RTKs are mostly activated by polypeptides but are not naturally sensitive to amino acids or light. Taking inspiration from Venus kinase receptors (VKRs), an atypical family of RTKs found in nature, we have transformed the human insulin (hIR) and hepatocyte growth factor receptor (hMET) into glutamate receptors by replacing their extracellular binding domains with the ligand‐binding domain of metabotropic glutamate receptor type 2 (mGluR2). We then imparted light sensitivity through covalent attachment of a synthetic glutamate‐based photoswitch via a self‐labelling SNAP tag. By employing a Xenopus laevis oocyte kinase activity assay, we demonstrate how these chimeric RTKs, termed light‐controlled human insulin receptor (LihIR) and light‐controlled human MET receptor (LihMET), can be used to exert optical control over the insulin or MET signaling pathways. Our results outline a potentially general strategy to convert RTKs into photoreceptors.     

Part 1: An Appraisal of New Radioisotope Techniques in the Study of Iodine Metabolism

The use of different radioiodines and technetium for the evaluation of the thyroid functions has been discussed. Preparation oe labelled iodotyrosines and labelled throxine is mentioned for the convey of different radiochemical tests and for the use of reference standards, necessary for the identification of separated amino acids. Paper chromatography and paper electrophoresis techniques are used for the identification and determination of iodinated amino acids or homones, either in the free state or bound to the proteins. Tc^99m is employed to substitute radioiodine in the study of uptake measurements of the thyroid gland and to evaluate the excretion of the isotope in urine. Thiourea-S³⁵ is employed, for the first time to human, to study the metabolism of the substance in different thyroid disorders.     

新型喹唑啉类酪氨酸激酶化学抑制剂的设计与合成

以6-氨基藜芦酸和醋酸甲脒为起始原料,合成了一系列4-位具有不同芳胺基团,6,7-位引入不同取代基的新型喹唑啉类酪氨酸激酶化学抑制剂,其结构经1H NMR表征.     

水杨醛酪氨酸铜配合物合成和EPR波谱

A new Schiff base derived from tyrosine and salicylidene and its copper(Ⅱ) complex have been synthesized and characterized by elemental analyses,molar conductances,thermal analyses,infrared spectra,electronic spectra and EPR spectra.The composition of the complex is K[CuL(Ac)]•H2O, where L=H13C16NO4. EPR spectra of the copper(Ⅱ) complex were investigated in various solvents at different temperatures.It is found that the linewidth of four hyperfine lines on solution spectra at room temperature is unequal and changes with mⅠ ,this could be satisfactorily explained by the relaxation effect.The relaxation time and the relaxation rate were calculated.By using spectral parameters from solution spectra at low temperature,the bonding parameters of Cu(Ⅱ) complex were calculated.The bonding characterization and stability of the complex were disscussed.The results show that the in plane 螵瞓ond and the in plane 皙瞓ond in the complex all play an important role.     

New Approach to Determination of Phenoxyl Free Radicals by Stopped‐Flow Spectrofluorimetry

Abstract

A simple and highly sensitive method to quantify the rates of production of phenoxyl radicals in enzyme reaction is described. This method employs the peroxidase‐catalyzed reaction between chlorophenols and hydroperoxide to generate phenoxyl free radicals, which can enhance dimerization of L‐tyrosine. The product, dityrosine, was monitored fluorometrically at the excitation/emission wavelength of 320/410 nm and the initial rate of accelerated‐accumulation of dityrosine represents the formation rate of phenoxyl free radicals. With this method, the phenoxyl radicals generated in oxidation of chlorophenols with hydrogen peroxide, catalyzed by horseradish peroxidase, were investigated. Phenoxyl radicals generated from as low as 5.0×10^?9 M 2,4‐dichlorophenol, for example, can be readily detected with a relative standard deviation of 2.6% for 9 replicated determination. The detection limits of phenoxyl radicals produced by various chlorophenols are 4.2×10^?9, 1.1×10^?9, 1.0×10^?10, 2.8×10^?8, and 1.1×10^?7 M for 2‐chlorophenol, 4‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, and 2,3,4,6‐tetrachlorophenol, respectively. The possible pathway of the reaction is proposed. The protocol is suitable for quantification of free radicals in enzyme reaction and shows promise in being applied to biological systems.     

Benzoylphosphonate-Based Photoactive Phosphopeptide Mimetics for Modulation of Protein Tyrosine Phosphatases and Highly Specific Labeling of SH2 Domains

A light switch for phosphotyrosine- recognizing proteins: Irradiation of the bioisosteric benzoylphosphonate suffices to "turn off" the activity of target proteins and to label them covalently. Photoactive bioisosters may find applications in functional cell biology, bioanalytics, and proteome research.     

Improved Synthesis of Gefitinib and Erlotinib Hydrochloride‐ Anticancer Agents

A highly efficient and commercially viable process for the synthesis of 6,7‐dihydroxy‐4‐anilinoquinazoline derivatives gefitinib (1) and erlotinib hydrochloride (2), used for the treatment of non‐small cell lung cancer (NSCLC) and pancreatic cancer, is reported. This new process has improved yields and avoids the unstable 4‐chloroquinazoline intermediate. The intermediates and final products were characterized by ¹H and ¹³C nuclear magnetic resonance (NMR), mass spectra (MS), and elemental analysis, and purities of final products were determined by high performance liquid chromatogram (HPLC) and potentiometric titration methods.     

LHMDS mediated tandem acylation-cyclization of 2-aminobenzenecarbonitriles with 2-benzymidazol-2-yl acetates: a short and efficient route to the synthesis of 4-amino-3-benzimidazol-2-ylhydroquinolin-2-ones

We herein describe the discovery of a mild, one-pot tandem acylation-cyclization for the synthesis of 4-amino-3-benzimidazol-2-ylhydroquinolin-2-ones from 2-aminobenzenecarbonitriles and ethyl 2-benzimidazol-2-yl acetates.     

Synthesis of mangiferin derivates and study their potent PTP1B inhibitory activity

Protein tyrosine phosphatase 1B (PTP1B) has received considerable attention from the drug industry as a potential treatment for diabetes mellitus.Mangiferin has been reported to possess significant antidiabetic activity.Based on the previous study,eight new mangiferin derivates were synthesized and evaluated for their PTP1B inhibitory activity.Some of them displayed good inhibitory activity on PTP1B.