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1.
Chemical investigation of Saussurea licentiana led to the isolation of ten compounds, and their structures were identified to be dia-aurantiamide acetate (1), (+)-pinoresinol 4-O-β-D-glucoside (2), encelin (3), apigenin (4), luteolin (5), jaceosidin (6), luteolin -7-O-β-D- glucopyranoside (7), α-amyrin (8), β-amyrin (9), taraxasterol (10) on the basis of mass and NMR spectra. This is the first report on the occurrence of compounds 1, and 2 in the genus Saussurea while 1 is reported for the first time from Asteraceae. This work also represents the first phytochemical work on the whole plants of S. licentiana. 相似文献
2.
Eduardo M.N. Nakashima Akihiro Kudo Yuri Iwaihara Mitsuru Tanaka Kiyoshi Matsumoto Toshiro Matsui 《Analytical biochemistry》2011,414(1):109
The liquid chromatography–multiple reaction monitoring–tandem mass spectrometry (LC–MRM–MS/MS) method using 13C stable isotope-labeled dipeptides was newly developed to simultaneously determine the absorption of three antihypertensive peptides (Val-Tyr, Met-Tyr, and Leu-Tyr) into blood of spontaneously hypertensive rats in one run-in assay. After extracting 13C-labeled peptides in blood sample with a C18 cartridge, the extract was applied to a 13C monoisotopic transition LC–MRM–MS/MS system with d-Val-Tyr included as internal standard. An excellent separation of each dipeptide in LC was achieved at the elution condition of 5–100% methanol in 0.1% formic acid at a flow rate of 0.25 ml/min. The 13C-labeled peptides ionized by electron spray were detected in the positive ion mode within 15 min. The established method showed high reproducibility with less than 10% coefficient of variation as well as high accuracy of more than 85%. After the administration of a mixture containing the three 13C-labeled dipeptides to rats at each dose of 30 mg/kg, we could successfully determine the intact absorption of each 13C-labeled peptide with the maximal absorption amount of 1.1 ng/ml plasma for Val-Tyr by the proposed LC–MRM–MS/MS method. 相似文献
3.
由于蛋白质亚细胞位置与其一级序列存在很强的相关性,利用多样性增量来描述蛋白质之间氨基酸组分和二肽组分的相似程度,采用修正的马氏判别式(这里称为IDQD方法)对分枝杆菌蛋白质的亚细胞位置进行了预测。利用Jackknife检验对不同序列相似度下的蛋白质数据集进行了预测研究,结果显示,当数据集的序列相似度小于等于70%时,算法的预测精度稳定在75%左右。在对整体852条蛋白质的预测成功率达到87.7%,这一结果优于已有算法的预测精度,说明IDQD是一种有效的分枝杆菌蛋白质亚细胞预测方法。 相似文献
4.
《Bioorganic & medicinal chemistry letters》2014,24(6):1511-1518
A series of dipeptide derivatives from dehydroabietic acid were designed and synthesized as novel antitumor agents. The antitumor activities screening indicated that many compounds showed moderate to high levels of inhibition activities against NCI-H460, HepG2, SK-OV-3, BEL-7404, HeLa and HCT-116 cancer cell lines and that some displayed more potent inhibitory activities than commercial anticancer drug 5-fluorouracil. The mechanism of representative compound 7b was studied by AO/EB staining, Hoechst 33258 staining, JC-1 mitochondrial membrane potential staining, TUNEL assay, DNA ladder assay and flow cytometry, which exhibited that the compound could induce apoptosis in HeLa cells. Further investigation showed that compound 7b induced apoptosis of HeLa cells through a mitochondrial pathway. 相似文献
5.
Zhong-Zhou Chen Yan-Mei Li Xi Peng Fu-Rong Huang Yu-Fen Zhao 《Journal of Molecular Catalysis .B, Enzymatic》2002,18(4-6):243-249
A crude lipase, Newlase F, was used to remove C-terminal protecting groups from dipeptide esters. Hydrolysis of dipeptide n-heptyl esters with Newlase F was conducted in aqueous media containing acetonitrile. The optimum pH and temperature of lipase in Newlase F were 7.0 and 30 °C, respectively. Low level acetonitrile promoted the hydrolysis of dipeptide n-heptyl esters, while high level acetonitrile inhibited the hydrolysis. However, the protease activity in Newlase F was significantly inhibited by acetonitrile. Lipase in Newlase F worked better in a medium containing water-miscible organic solvents than in water-immiscible ones. N-terminal protecting groups were not affected by the protease in the crude enzyme. It was found that the protease in Newlase F did not hydrolyze amide bond with hydrophilic amino acids on either side under these conditions (pH 7.0, room temperature). Newlase F may consequently be used widely in the synthesis of peptide conjugates. The crude enzyme was immobilized on SBA-15 mesoporous molecular sieve. The lipase activity of immobilized preparation was more active on hydrolysis of C-terminal protecting groups and stable than the free enzyme. The immobilization also reduced the protease activity. 相似文献
6.
Vishnu Mohanan Catherine Leimkuhler Grimes 《The Journal of biological chemistry》2014,289(27):18987-18998
Microbes are detected by the pathogen-associated molecular patterns through specific host pattern recognition receptors. Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) is an intracellular pattern recognition receptor that recognizes fragments of the bacterial cell wall. NOD2 is important to human biology; when it is mutated it loses the ability to respond properly to bacterial cell wall fragments. To determine the mechanisms of misactivation in the NOD2 Crohn mutants, we developed a cell-based system to screen for protein-protein interactors of NOD2. We identified heat shock protein 70 (HSP70) as a protein interactor of both wild type and Crohn mutant NOD2. HSP70 has previously been linked to inflammation, especially in the regulation of anti-inflammatory molecules. Induced HSP70 expression in cells increased the response of NOD2 to bacterial cell wall fragments. In addition, an HSP70 inhibitor, KNK437, was capable of decreasing NOD2-mediated NF-κB activation in response to bacterial cell wall stimulation. We found HSP70 to regulate the half-life of NOD2, as increasing the HSP70 level in cells increased the half-life of NOD2, and down-regulating HSP70 decreased the half-life of NOD2. The expression levels of the Crohn-associated NOD2 variants were less compared with wild type. The overexpression of HSP70 significantly increased NOD2 levels as well as the signaling capacity of the mutants. Thus, our study shows that restoring the stability of the NOD2 Crohn mutants is sufficient for rescuing the ability of these mutations to signal the presence of a bacterial cell wall ligand. 相似文献
7.
Xu L Zhang L Jones R Bryant C Boddeker N Mabery E Bahador G Watson J Clough J Arimilli M Gillette W Colagiovanni D Wang K Gibbs C Kim CU 《Bioorganic & medicinal chemistry letters》2011,21(6):1670-1674
There is an urgent need for the development of novel antimicrobial agents that offer effective treatment against MRSA. Using a new class of dipeptide antibiotic TAN-1057A/B as lead, we designed, synthesized and evaluated analogs of TAN-1057A/B. Several novel dihydropyrimidinone antibiotics demonstrating comparable antibiotic efficacy while possessing favorable selectivity were identified. 相似文献
8.
Kihara M Igarashi M Suzuki T Itou F Kozeni S Toyomane M Nakano J Yamai I 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2011,158(4):444-449
The effect of intra-gastric infusion of skipjack tuna (Katsuwonus pelamis) muscle soluble extract and of carnosine, anserine and histidine, on pepsin-like protease activity was studied in the isolated, externally batch-cultured stomach of the rockfish (Sebastes schlegelii). Stomach was isolated from the fish, then intragastrically infused with the above solutions or with a balanced saline solution (control solution) as the stimulant at 0.1 mL/min for 6h. Intra-gastric efflux was collected for measurement of pepsin-like protease activity. Skipjack tuna soluble extract, but not carnosine, anserine or histidine alone caused significant enhancement of pepsin-like protease activity during the infusion. Pepsin-like protease activity from skipjack tuna soluble extract responded immediately after infusion and was kept for 150 min after infusion. Stomach motility at the end of infusion was also observed. These results suggest that isolated stomach can receive mucosal side stimulants in vitro. It is likely that some effective components for stomach digestion in fish exist in skipjack tuna soluble extract. 相似文献
9.
This study is the first to demonstrate cloning of alr0882, a hypothetical protein gene of Anabaena PCC7120, its heterologous expression in Escherichia coli strain LN29MG1655 (?uspA::Kan) and functional complementation of abiotic stress tolerance of E. coli UspA. The recombinant vector pGEX-5X-2-alr0882 was used to transform ?uspA E. coli strain. The IPTG induced expression of a 56.6 kDa GST fusion protein was visualized on SDS–PAGE and attested by immunoblotting. E. coli ?uspA strain harboring pGEX-5X-2-alr0882 when grown under carbon, nitrogen, phosphorus and sulphur limitation and abiotic stresses e.g. nalidixic acid, cycloserine, CdCl2, H2O2, UV-B, phenazine methosulphate (PMS), dinitrophenol (DNP), NaCl, heat, carbofuron and CuCl2 demonstrated about 22.6–51.6% increase in growth over the cells transformed with empty vector. Expression of alr0882 gene in mutant E. coli as measured by semi-quantitative RT-PCR at different time points under selected treatments reaffirmed its role in tolerance against stresses employed in this study. Thus the results of this study vividly demonstrated that the novel protein alr0882, although appreciably different from the known UspA of E. coli, offers tolerance to abiotic stresses hence holds potential for the development of transgenic cyanobacteria. 相似文献
10.
Through a systematic reduction of peptide structure, a series of 25 tripeptide and 5 dipeptide amide and alcohol analogs of enkephalin were synthesized and assayed in vitro on the stimulated guinea pig ileum. Tyr-Pro-Phe-NH2, Tyr-D-Ala-Phe-NH2, Tyr-D-Ala-Phe-ol and Tyr-D-Phe-Phe-NH2 had 20-25% the potency of Met-enkephalin. Four aromatic alkylamides of the dipeptide Tyr-D-Ala were made with benzylamine, phenethylamine, phenylpropylamine and phenylbutylamine. All had full naloxone reversible enkephalin-like activity in the ileum assay. Tyr-D-Ala-phenylpropylamide has about 80% the potency of Met-enkephalin in vitro, and is equipotent with Tyr-D-Ala-Gly-Phe-Met-NH2 in producing analgesia in mice after intraventricular administration. Tyr-D-Phe-NH2 is the smallest peptide to show full intrinsic enkephalin-like activity in vitro, although its potency is very low. 相似文献