Synthesis of a highly hydrophobic cyclic decapeptide by solid-phase synthesis of linear peptide and cyclization in solution

A general method was described to synthesize a highly hydrophobic cyclic peptide,cyclo[LWLWLWLWLQ]where underlines indicate D-configuration of the amino acid,by a two-step solid-phase/solution synthesis strategy.The linear decapeptide was assembled by standard Boc chemistry on solid-phase and subsequently cyclized in solution with high efficiency and reproducibility. In subsequent purification by semi-preparative HPLC,50%(v/v) DMF/H_2O was employed as the solvent to overcome the difficulty of solubilization...

Solid Phase Peptide Synthesis of Fusukang for AIDS

A 36-residue peptide is designed to cure acquired immunodeficiency syndrome(AIDS), and is synthesized by the manual solid phase peptide synthesis technique. Different reaction conditions of the synthesis process were discussed. Stirring efficiency of mechanics and nitrogen was compared. The mechanical method displays a predominant performance. Although the coupling efficiencies of diisopropylcarbodiimide(DIC) and dicyclohexylcarbodiimide(DCC) are virtually identical, DIC offers several advantages over DCC in practice due to different physical characters. Wash conditions after deprotection and coupling were investigated to monitor washing efficiency. 0.369 2 g crude peptide was obtained.

Solid-Phase Enzymatic Peptide Synthesis to Produce an Antioxidant Dipeptide

Peptide bond synthesis is favorable to the production of bioactive small peptides. However, the abuse of toxic reagents remains an issue for chemical synthesis method, whereas the low product yield and purity limit the widespread use of enzymatic method. In this study, a new solid-phase enzymatic peptide synthesis(SPEPS) strategy was developed to produce an antioxidant tyrosine-alanine dipeptide(Tyr-Ala) by using recombinant carboxypeptidase Y(CPY) as the catalyst. The general SPEPS procedure involves three steps. First, the N-protected acyl donor was covalently attached to solid resin. Second,the peptide bond was condensed between the acyl donor and the nucleophile under the catalysis of CPY. Finally, one-step cleavage was performed to remove the protecting group and cleave the peptides from solid resin. Upon the optimization of reaction conditions, 77.92%(±2.723%) yield of Tyr-Ala with high product purity of 90.971%(±2.695%) was obtained.In addition, the antioxidant activity of Tyr-Ala was determined by ABTS method, indicating that the synthesized Tyr-Ala obtained by SPEPS showed a superior antioxidant capability compared with commercial glutathione.

Synthesis of Nitrogen-containing Cyclopeptides from N-Terminal Lysine Precursor on Solid Supports

Three synthetic routes for the preparation of nitrogen containing cyclic compounds have been developed, in which the assembling of Fomc-Lys(Boc) residue at N-terminal of resin-bound intermediates is a key prerequisite. Six peptides with nitrogen containing local cyclic structure were efficiently synthesized in good yield starting from chloromethyl resin.

Study on Chemical Synthesis and Insecticidal Activity of Peptideκ-CTx-btg02

[Objectives]This study was conducted to investigate the chemical synthesis of peptideκ-CTx-btg02.[Methods]Linear peptideκ-CTx-btg02 was synthesized by solid phase peptide synthesis(SPPS).After oxidation and folding of the linear peptide,mass spectrometry identification and high performance liquid chromatography(HPLC)purification were performed.Then,the MTT method and insect injection method were applied to study its insecticidal activity.[Results]The peptideκ-CTx-btg02 was successfully synthesized by the SPPS method,and identified for the formation of disulfide bonds by mass spectrometry identification,and the purity after HPLC separation was greater than 95%.The MTT experiment showed that the peptideκ-CTx-btg02 could inhibit the growth of insect cells sf9,with a half effective dose of 0.13 nM.The insect injection experiment showed that the peptideκ-CTx-btg02 could effectively kill Tenebrio molitor,with a half lethal dose of 15.6 nM.The results of the electrophysiological experiment showed that 10μM peptideκ-CTx-btg02 had no blocking activity on murine acetylcholineα2β3 andα3β4.Therefore,the peptideκ-CTx-btg02 had a good inhibitory effect on the growth of insect cells,highly effective insecticidal activity and weak mammalian toxicity.[Conclusions]This study lays a foundation for the development of new,safe and efficient peptide biological insecticides.

Solid-phase Synthesis of PNA Monomer by Ugi Four-component Condensation Reaction

Peptide nucleic acids (PNA) oligomers were synthesized in most cases by peptide synthesis from N-protected monomers. In this work a new method of obtaining PNA monomer by Ugi four-component condensation reaction was tested by solid-phase synthesis. The Fmoc protected PNA monomer was build up with thymin-1-yl acetic acid, 3-methylbutyl aldehyde, Fmoc protected aminoethyl isocyanide and Gly-Wang resin.

Synthesis of Peptoid Nucleic Acid with Thymine as Nucleic Base

The synthesis of peptoid nucleic acid bearing thymine as nucleobase has been achieved. This modified oligonucleotide showed good hybridization with DNA.

Preparation and Insecticidal Activity of Sea Anemone Peptide AP-GI from Aiptasia pallida

[Objectives] This study was conducted to synthesize sea anemone peptide Ap-GI and investigate its insecticidal activity. [Methods] The linear peptide Ap-GI was synthesized by solid phase peptide synthesis(SPPS), and the linear peptide was subjected to the two-step oxidative folding, mass spectrometry identification and high performance liquid chromatography(HPLC) purification. Then, the MTT method and insect injection method were used to study its insecticidal activity. [Results] The synthesized sea anemone peptide had a purity of 95%. The test results of the MTT method showed that the peptide Ap-GI had the activity of inhibiting the growth of insect cells sf9 with the median effective dose of 0.7 nM;and the test results of the injection method on yellow mealworms showed that the peptide Ap-GI had high insecticidal activity, and the median lethal dose was 16.9 nM. [Conclusions] The sea anemone peptide Ap-GI from Aiptasia pallida has a good inhibitory effect on the growth of insect cells and high-efficiency insecticidal activity, which can lay a foundation for the development of new, safe and efficient peptide biological insecticides.

USE OF HOEC ACTIVE ESTERS IN SOLIDPHASE PEPTIDE SYNTHESIS——THE SYNTHESIS OF GROWTH HORMONE RELEASING PEPTIDE

N-hydroxysuccinimide (HOSU) active esters have gained wide application in peptide synthesis, especially in the synthesis of longer peptides by segment conden sation, for they can avoid racemization during coupling processes. However, the HOSU active ester method is prone to side reactions, forming undesirable by-products such as succinimide-oxycarbonyl-alanine N-hydroxysuccinimide ester (Ⅰ) in activating steps and compound (Ⅱ) in the coupling steps sterically hindered by amino acids (proline, valine, isoleucine, etc.).

An Improved Synthesis of Laminin Fragment CR9

Laminin nonapeptide CR9 was synthesized via two different methods. A notably enhanced yield (46.8%) was obtained from method B compared to that (12.4%) from standard protocol (method A).

转铁蛋白受体亲和肽衍生物的制备

以2-氯三苯甲基氯(2-CTC)树脂为固相载体、N-芴甲氧羰基(Fmoc)保护氨基酸为原料、N,N′-二异丙基碳二亚胺(DIC)和1-羟基苯并三唑(HOBt)为缩合剂,采用Fmoc固相合成法制备了一种转铁蛋白受体亲和肽(transferrin receptor binding peptide,TfRBP)衍生物,其纯品的HPLC纯度为97.9%,总收率为40.3%,经ESI-MS鉴定其相对分子质量与理论值一致。该方法操作简便、合成周期短、总收率高,为进一步构建TfR靶向多肽-药物偶联物奠定了基础。

布鲁氏菌侵染抑制剂的合成改造及活性研究

目的:研究一种新型抗布鲁氏菌的药物,以求布鲁氏菌病的功能性治愈。方法:通过多肽固相合成法(solid phase peptide synthesis,SPPS)和在液相中进行化学反应等操作,根据布鲁氏菌侵染抑制剂OP11线性肽结构合成改造了三个环肽,即环OP11肽、三氮唑丁肽和三氮唑戊肽。通过二硫苏糖醇(dithiothreitol,DTT)测试了目标多肽的稳定性,并使用绵羊布鲁氏菌测定多肽的抗菌活性。结果:使用绵羊布鲁氏菌测试了目标肽的最低抑菌浓度(minimum inhibitory concentration,MIC),测试结果显示,线性OP11肽、环OP11肽、三氮唑丁肽和三氮唑戊肽的MIC值分别为1.281、0.043、0.059、0.052μg/mL。在DTT存在下,环OP11肽中的二硫键可发生还原反应,其半衰期为8 h,而三氮唑丁肽和三氮唑戊肽对DTT稳定。结论:经改造得到的环OP11肽对绵羊布鲁氏菌抑制作用最强,含三氮唑环的丁肽和戊肽的抗菌活性仅次于含有二硫键的环OP11肽。此外,含有三氮唑环的多肽较含有二硫键的多肽化学性质更为稳定。

Total synthesis of cyclic heptapeptide euryjanicin B

The first synthesis of the naturally occurring cyclic peptide euryjanicin B has been achieved.A general method was described to synthesize the cyclic peptide by a two-step solid-phase/solution synthesis strategy.All the amino acids in this study are L-configuration. The linear heptapeptide was assembled by standard Fmoc chemistry on solid-phase and subsequently cyclization was carried out by solution method.

STUDIES ON PEPTIDES (Ⅵ)——SYNTHESIS AND PRIMARY BIOLOGICAL ACTIVITY EXAMINING OF THREE FRAGMENTS (93-102, 84-102, 25-38) OF TRANSFORMING GROWTH FACTOR-β

Transforming growth factor-β(TGF-β)is a multifunctional regulatory molecule existing in a wide variety of both normal and neoplastic cells. In order to evaluate the structure-function relationship of TGF-β, we have synthesized a series of its important fragments by manual stepwise solid-phase methodology and studied their biological activity. In

芋螺毒素G1.9的氧化折叠及活性

【目的】通过合成芋螺毒素线性肽G1.9并优化氧化折叠体系,测试其对昆虫细胞毒性,为新型多肽类杀虫剂的设计提供依据。【方法】采用固相多肽合成法(SPPS)制备含4个半胱氨酸的芋螺毒素线性肽G1.9并优化氧化折叠体系,采用一罐法氧化芋螺毒素G1.9并验证其生物活性。【结果与结论】采用SPPS法成功地合成了线性肽G1.9,优化获得芋螺毒素G1.9-G型异构体的最佳氧化折叠体系是在0.1 mol/L碳酸氢铵缓冲液(pH 8.0)中氧化36 h。MTT法实验表明G1.9-G能显著抑制昆虫细胞sf9的生长,为后续研究开发新型、安全和高效的多肽类生物杀虫剂奠定基础。

一种灯盏花乙素-多肽的工艺研究

对灯盏花乙素-HomoArg-Gly-Asp-Trp-NH_(2) 的合成进行工艺研究。采用Fmoc固相合成法合成目标多肽。由于灯盏花乙素中含有多个酚羟基,粗肽在裂解时很大概率会被氧化,氧化杂质将增加粗肽纯化的难度并影响收率。对裂解体系及纯化条件进行研究,结果发现,采用3-巯基丙酸/TFA/Tis/H_(2) O裂解体系及特定的洗脱梯度,可以获得纯度98%以上的目标多肽。通过工艺研究,确定了目标多肽的裂解体系和洗脱梯度,提高了纯化效率和总体产率,为相似结构的合成和产业化提供了参考。

厚壳贻贝组蛋白H2的免疫响应及其衍生肽抑菌活性

为深入了解组蛋白及其衍生肽在贻贝免疫过程中的作用,实验采用荧光定量PCR(qPCR)技术对厚壳贻贝组蛋白H2A和H2B进行微生物胁迫后的表达量变化进行分析。在此基础上,对厚壳贻贝组蛋白H2A和H2B基于其N端序列设计的衍生肽段(分别为Coruscusin-Ⅰ和Coruscusin-Ⅱ)进行固相化学合成、圆二色性光谱分析以及抑菌活性验证。结果显示,厚壳贻贝组蛋白H2A和H2B在不同组织中,对不同微生物胁迫均产生明显的表达量上调,且在血细胞中表现出对真菌和革兰氏阴性菌的敏感性,在鳃组织中表现为对革兰氏阳性菌的敏感性;而在消化腺组织中,H2A对革兰氏阳性菌较为敏感,但H2B对真菌和革兰氏阴性菌较为敏感。厚壳贻贝组蛋白衍生肽段Coruscusin-Ⅰ和Coruscusin-Ⅱ在非极性溶液中,其螺旋含量明显上升,且二者对革兰氏阳性菌和革兰氏阴性菌均具有明显的抑菌活性,但Coruscusin-Ⅱ对真菌的抑制活性较Coruscusin-Ⅰ强。进一步的螺旋结构预测结果表明,2种衍生肽序列中碱性氨基酸的种类及分布特征可能是其抑菌活性差异的内在原因。本研究为了解组蛋白及其衍生肽在贻贝免疫过程中的作用及其机制奠定了基础,也为开发贻贝组蛋白衍生肽为来源的新型生物抗生素提供了科学依据。

An expedient synthesis of peptidyl N-alkylamides by "HOPE" strategy

We have developed an expedient approach,＂HOPE＂（hybrid orthogonal protocol with ease） strategy for the synthesis of peptidyl N-alkylamides.This new strategy was characterized by following points：incorporating Boc and Fmoc protocols together on Merrifield resin,removal of SPG（side-chain protecting groups） without the damage of linker structure on the resin,and the ammonolysis of linker as the last step could achieve the introducing N-alkylamide structure into C-terminal and releasing product from resin-support simultaneously.In present work,eight peptidylamides with different alkylsubstitution at C-terminal were conveniently synthesized by HOPE strategy.

Synthesis and DNA-binding ability of Spl protein zinc finger domain and its peptidomimetics

The second zinc finger fragment of Sp1 (Spl-ZF2), its mutant (Spl-ZF2/HT. E20→H, R23→T), and two mimic analogues (ZF20 and ZF15) were synthesized by stepwise solid phase technique. The CD spectra and UV-visible spectrum with CoCl2 indicated that the formation of zinc finger structure was affected not only by the hy-drophobic amino acids but also by the change of the distance between Cys and His. Gel-retardation electrophoresis as-says indicated that the Grlu and Arg residues are very important for recognition. A single zinc finger like Spl-ZF2 isable to bind DNA sequence specifically.

疏水载体辅助液相多肽合成与固相多肽合成工艺的比较

目的分别采用两种液相多肽合成法和固相多肽合成(SPPS)法对具有抗病毒活性的多肽RC-12进行合成工艺研究,通过工艺比较分析以研究其潜在的商业价值。方法分别采用Tag-OH液相法、BDK-OH液相法及SPPS法合成抗病毒多肽RC-12,并对三种不同的合成工艺进行物料消耗量、“三废”产生量、收率比较。结果比较Tag-OH液相法和BDK-OH液相法,两种方法的收率相差不大且都优于SPPS法;BDK-OH液相法物料消耗量和“三废”产生量高于Tag-OH液相法,但都远远低于SPPS法。结论Tag-OH液相法对合成多肽RC-12具有较好的工业研究意义和潜在的商业价值。