Simulation Analysis of Occupancy Rates of Baicalein， Quercetin and Galangin on Target Sites of Xanthine Oxidase / 中国实验方剂学杂志

Objective:To simulate the occupancy rates of baicalein， quercetin and galangin on the target sites of xanthine oxidase <italic>in vivo</italic>. Method:In this experiment， the half inhibitory concentration （IC₅₀） of febuxostat， baicalein， quercetin and galangin against xanthine oxidase were determined by <italic>in vitro</italic> enzymatic reaction. Binding free energy was predicted by molecular docking technology and their association rate constant （k_on） and dissociation rate constant （k_off） were determined by surface plasmon resonance technology. Based on measured binding kinetic parameters （k_on and k_off） and extracted pharmacokinetic data， the target occupancy model <italic>in vivo</italic> was established. Result:The IC₅₀values of febuxostat， baicalein， quercetin and galangin were 0.002 7， 1.63， 0.38， 1.59 µmol·L^-1， respectively. The IC₅₀ of febuxostat was very close to that reported in the literature. The predicted curve of target occupancy rate <italic>in vivo</italic> of febuxostat was consistent with its duration of clinical efficacy. When single intragastric administration of long-circulating liposomes of quercetin with dose of 100 mg·kg^-1 in rats， the time of target occupancy rate >70% <italic>in vivo</italic> lasted for about 3.9 h. When rats were orally administered baicalein and galangin with dose of 200 mg·kg^-1， the time of target occupancy rate >50% <italic>in vivo </italic>lasted for about 10 h and 1.7 h， respectively. Conclusion:The prediction model of xanthine oxidase target occupancy constructed by drug target binding kinetics and <italic>in vivo</italic> pharmacokinetic curves can effectively evaluate the <italic>in vivo</italic> inhibitory activity of compounds against the target.

Screening of 14-3-3τ protein inhibitors from natural products based on fluorescence spectroscopy, surface plasmon resonance and molecular docking technique / 国际药学研究杂志

Objective:To study and establish a method for the efficient screening of 14-3-3τ protein inhibitors from natural products, and analyze the sites of their interactions with the 14-3-3τ protein. Methods: The binding activity of natural compounds with the 14-3-3τ protein was tested by the liquid chromatography-fluorescence spectroscopy, and the binding activity of the potential compounds was further verified by the surface plasmon resonance(SPR)technique. The binding sites of the active compounds were predicted by the molecular docking technique. Furthermore, the key binding sites were selected and then validated using amino acid site-directed mutants. Results: A total of 17 different type compounds with potential 14-3-3τ binding activity were screened out from 82 natural products. The binding activi- ties of 10 compounds were verified by the SPR experiments. Then the binding sites of interactions between the 14-3-3τ protein and the 10 compounds were predicted by the molecular docking technology to be mainly at the Arg56, Arg127 and Y128A, dem- onstrate that the binding of five of the 10 compounds with the target protein was associated with the three sites Arg56, Arg127 and Tyr128. Conclusion: The established method is accurate and efficient, which could be used for rapid screening of small molecule 14-3-3τ inhibitors from natural products. The present study provides a reference and a new approach for the rapid screening of 14-3-3τ inhibitors for the new breast cancer therapeutic drugs.

Application of surface plasmon resonance biosensor in quantitative analysis re-search / 药学实践杂志

Surface plasmon resonance(SPR) is an optical phenomenon arises from mass changes on sensors based on in-teraction between substances ,which could monitor the interaction between biomolecules quickly and accurately .It has the ad-vantage of label-free ,high specificity ,high accuracy ,real-time and on-line monitoring ,which has attracted comprehensive at-tention in recent years .SPR biosensors could be applied in drug discovery ,clinical diagnosis ,food safety ,environment monito-ring and proteomics .In this manuscript ,the application of SPR biosensors in food safety ,environment monitor and biomedical analysis have been reviewed ,which could provide reference to related research .

Gold Nanoparticles synthesis, properties, and forthcoming applications – A review .

Gold nanoparticles (AuNPs) have several biomedical applications in diagnosis and treating of disease such as targeted chemotherapy and in pharmaceutical drug delivery due to their multifunctionality and unique characteristics. AuNPs can be conjugated with ligands, imaging labels, therapeutic drugs and other functional moieties for site specific drug delivery application. In this present review we are discussing the synthesis, properties, and forthcoming applications of gold nanoparticle (AuNPs) which is the most studied among all other metallic-nanoparticles. Here our main focus is to explain the AuNPs application in cancer treatment. AuNPs provides non-toxic carrier system for pharmaceutical drug and gene delivery applications. Currently various anticancer drugs are available but these are cause the necrosis of cancerous cell as well as normal cells. AuNPs cause the necrosis of only cancer cells therefore we can utilize it as a delivery vehicle as well as anticancer agent.

FGF2 de 18kDa e de 22.5kDa: sinalização molecular parácrina e funções biológias / FGF2 species of 18 and 22.5 kDa: paracrine molecular signaling and biological functions

FGF2 (Fibroblast Growth Factor 2), o fundador da família FGF, tem funções regulatórias na mitogênese, diferenciação, morfogênese e reparo tecidual. Diversas espécies moleculares de FGF2 compartilham uma seqüência C-terminal comum de 155 aminoácidos, pois se originam de diferentes sítios de iniciação de leitura de um único mRNA. O menor, o FGF2-18kDa, é liberado extracelularmente para se ligar a receptores específicos (FGFRs) para disparar as funções parácrinas e autócrinas pelas quais este fator é conhecido. Por outro lado, as espécies maiores (FGF2-21, 22, 22,5 e 34kDa) são intracelulares se ligam a parceiros moleculares desconhecidos para exercer funções intrácrinas ainda indefinidas. O objetivo desta tese foi produzir espécies recombinantes do FGF2-18 e FGF2-22,5, na forma de proteínas de fusão, para analisar funções biológicas e mecanismos de sinalização. Nas células malignas Y1 de camundongo, os recombinantes de FGF2-18kDa (FGF2-18, His-FGF2-18 e His-FGF2-18-ProA) dispararam uma resposta antagônica estimulando as vias de sinalização mitogênica, mas bloqueando o ciclo celular. Nos fibroblastos não tumorigênicos Balb3T3, estes mesmos recombinantes de FGF2-18kDa dispararam apenas a resposta mitogênica clássica. Todos os efeitos biológicos destes recombinantes de FGF2-18kDa foram bloqueados pelo inibidor específico da proteína quinase de tirosina dos FGFRs, PD173074, demonstrando que são respostas intermediadas pelos FGFRs. Portanto, os domínios estruturais adicionados aos recombinantes de FGF2-18kDa não impediram que estas proteínas se ligassem e ativassem os FGFRs. Por outro lado, o recombinante His-FGF2-22,5 dispara apenas as vias de sinalização mitogênica em ambas as células Y1 e 3T3, mas este efeito biológico não é inibido por PD173074. Estes resultados sugerem que a seqüência N-terminal de 55 resíduos, rica em aminoácidos básicos, impede que o FGF2-22,5kDa se ligue e/ou ative os FGFRs. Entretanto, o recombinante His-FGF2-22,5ProA dispara a resposta...

FGF2 (Fibroblast Growth Factor 2), the founder of the FGF family, has regulatory functions in mitogenesis, differentiation, morphogenesis and tissue repair. Multiple FGF2 molecular species, sharing a C-terminal sequence of 155 amino acids, are translated from different iniciation sites of the same mRNA. The smaller, the FGF2-18kD, is extracellularly released to bind to specific membrane receptors (FGFRs), performing paracrine and autocrine functions. On the other hand, the larger FGF2s (21, 22, 22.5 and 34kDa) are intracellular species that bind to unknown partners to play still undefined intracrine roles. The aim of this thesis was to produce recombinant species of FGF2-18kDa and FGF2-22,5kDa, in the form of fusion proteins, to analyze functions and signaling mechanisms. In mouse Y1 malignant cells, FGF2-18kD recombinants (FGF2-18kDa and His-FGF2-18kDaProA) triggered an antagonistic response activating mitogenic signaling pathways, but blocking the cell cycle. However, in non tumorigenic Balb3T3 fibroblasts, these same FGF2-18kD recombinants only elicited the classical mitogenic response. All biological effects of these FGF2-18kD recombinants were blocked by the specific inhibitor of FGFR-protein-tyrosine-kinases, PD173074, demonstrating that these responses are mediated by FGFRs. Therefore, the new peptide domains added to FGF2-18kD did not prevent these recombinant fusion proteins to bind and activate FGFRs. Conversely, the recombinant His-FGF2-22,5kDa triggered only mitogenic signaling pathways in both Y1 and Balb3T3 cells, a biological effect not inhibited by PD173074. These results suggested that the additional basic-rich N-terminal sequence of 55 amino acid residues, found in FGF2-22,5kDa, prevents this FGF2 species from binding and / or activate FGFRs. However, surprisingly, the recombinant His-FGF2-22kDaProA triggered the antagonistic response characteristic of FGF2-18kDa. These results imply that the ProA-domain added to the C-terminal end...