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Shanghai, China

Bao Y.,Sundia MediTech | Wang Q.,Suzhou Kangrun Pharmaceutical Testing Service Inc. | Tang P.,Suzhou Kangrun Pharmaceutical Testing Service Inc.
Journal of Mass Spectrometry | Year: 2013

A novel, rapid and sensitive liquid chromatography/quadrupole linear ion trap mass spectrometry [LC-ESI-(QqLIT)MS/MS] method was developed and validated for the quantification of protopanaxadiol (PPD) in rat plasma. Oleanolic acid (OA) was used as internal standard (IS). A simple protein precipitation based on acetonitrile (ACN) was employed. Chromatographic separation was performed on a Sepax GP-C18 column (50 × 2.1 mm, 5 μM) with a mobile phase consisting of ACN-water and 1.5 μM formic acid and 25 mM lithium acetate (90: 10, v/v) at a flow rate of 0.4 ml/min for 3.0 min. Multiple-reaction-monitoring mode was performed using lithium adduct ion as precursor ion of m/z 467.5/449.4 and 455.6/407.4 for the drug and IS, respectively. Calibration curve was recovered over a concentration range of 0.5-100 ng/ml with a correlation coefficient >0.99. The limit of detection was 0.2 ng/ml in rat plasma for PPD. The results of the intraday and interday precision and accuracy studies were well within the acceptable limits. The validated method was successfully applied to investigate the pharmacokinetic study of PPD after intravenous and gavage administration to rat. Copyright © 2013 John Wiley & Sons, Ltd. Source

Chen A.,Central China Normal University | Bao Y.,Sundia MediTech | Ge X.,Central China Normal University | Shin Y.,Pacific Northwest National Laboratory | And 2 more authors.
RSC Advances | Year: 2012

Phosphorylated p53 at serine 15 (phospho-p5315) is a potential biomarker of gamma-radiation exposure. In this paper, we described a new magnetic particle (MP)-based electrochemical immunoassay of human phospho-p5315 using carbon nanospheres (NS) and protein cage nanoparticles (PCN) for signal amplification. Greatly enhanced sensitivity was achieved for three reasons: 1) PCN and the p5315 signal antibody (p5315 Ab2) are linked to the carbon NS (PCN-p53 15 Ab2-NS) as a label; 2) PCN increases the amount of metal ions in the cavity of each apoferritin; 3) MPs capture a large amount of primary antibodies. Protein cage templated metallic phosphates, instead of enzymes, as multi-labels have the advantage of eliminating the addition of mediator or immunoreagents and, thus, makes the immunoassay system simpler. Subsequent stripping voltametric analysis, detected olead ions on a disposable screen-printed electrode. The response current was proportional to the phospho-p5315 concentration in the range of 0.02 to 20 ng mL -1 with a detection limit of 0.01 ng mL-1, which was 30-fold lower than that of the ELISA measurement of phospho-p5315. This method shows an acceptable stability and reproducibility and the assay results for phospho-p5315-spiked human serum presented good recovery rates. © 2012 The Royal Society of Chemistry. Source

Yang J.,Sundia MediTech
Proteomics Research Journal | Year: 2012

The effort to develop better description of protein three-dimensional folding structures has dominated biochemistry and drug discovery research for more than 70 years since Pauling first defined the helical configurations as secondary structure for protein in 1940. The challenge is how to acquire a complete description of protein folding shapes from N-terminal to C-terminal, including regular secondary structure as well as irregular tertiary structure. Here, a novel description method is introduced, which a set of 27 vectors is rigorously derived mathematically from an enclosed space. Each vector represents a three-dimensional folding shape of five successive Cα atoms, and the protein conformation can be completely described along protein backbone. These vectors are expressed by 27 alphabetic symbols, which are called as protein folding shape code (PFSC). Consequently, with PFSC, the folding conformation of any protein with given three-dimensional structure is able to be converted into a simple one-dimensional alphabetic string without gap. Furthermore, to take the advantage of one-dimensional description of folding shapes, the protein conformational structures are able to be compared with Needleman-Wunsch alignment algorithm. The global similarity of protein 3D structures is able to be assessed by a value of protein folding structure alignment score (PFSA-S) as a quantitative measurement, and the similarity and dissimilarity of local structures is able to be examined by alignment table. The results show that this approach has the capability not only to distinguish protein conformers with relatively high similarity, but also to compare proteins with diverse degrees in structural homology. Therefore, this approach provides a consistent procedure, and it produces a unique score for assessment of similarity in protein structure comparison. The significant is that the complete description of protein folding shapes provides a simple and effective means to screen protein database, compare protein structures, search protein fragment and probe drug binding site, study protein mutation and protein misfolding and so on. © 2012 Nova Science Publishers, Inc. Source

Zeng Y.,Sundia MediTech | Zeng Y.,Shanghai University of Traditional Chinese Medicine | Shao D.,Shanghai University of Traditional Chinese Medicine | Fang Y.,East China Normal University
Analytical Letters | Year: 2011

An on-line two-dimension microflow liquid chromatography was developed for better separation and analysis of the highly complex ingredients of medicinal preparation of traditional Chinese medicine Coptis Chinensis Franch. A two-valve switching system was utilized for two-dimension chromatography with strong cation exchange and reverse-phase capillary columns separation. The components were separated well by this system and yielded over 420 peaks. Under the optimal condition, 4 compounds were detected quantitatively. A good linear relationship was obtained from 0.2μgmL -1 to 24μgmL -1with detection limits (S/N=3) ranging from 0.05μgmL -1 to 0.2μgmL -1for the compounds. We demonstrated that the method can be successfully applied to the analysis of a natural complex sample, with satisfactory results. © Taylor & Francis Group, LLC. Source

Zheng K.,Jilin Institute of Chemical Technology | Yang H.,Jilin Gongmao Xuexiao | Zhao X.,Micro Pharmatech Ltd. | Jiang Y.,Sundia MediTech | And 2 more authors.
Chemical Research in Chinese Universities | Year: 2014

We used a new approach, protein folding shape code(PFSC), to predict the potential staurosporine binding sites in protein kinases. Firstly, all available three dimensioned(3D) structures of protein kinases in protein databank(PDB) were converted into one-dimensional PFSC description, based on which a PFSC-kinome library was constructed. Secondly, a set of protein kinase-staurosporine complexes were analyzed to define the common structural features of the binding sites. Thirdly, the structural features of the staurosporine binding sites were used to virtually screen the PFSC-kinome library to predict multiple protein receptors that have potential binding capacity for staurosporine. Collectively, the development of the similar method for predicting drug binding site demonstrates that virtual screening protein database can provide valuable information on drug discovery and understanding of pharmacological pathways. © 2014 Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH. Source

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