1.Detection and Partial Characterization of γ-glutamyltranspeptidase from Cordyceps sinensis Mycelia
Jianglan YUAN ; Xu KANG ; Zheng HU ; Guolin ZOU
China Biotechnology 2008;28(10):100-105
γ-glutamyltranspeptidase was detected from the cultured mycelia of Cordyceps sinensis (CSGT). Km and Vmax of CSGT was 2.54×10-4 mol/L and 0.1808 mol/L·min respectively when L-glutamic acid 5-(4-nitroanilide) (GpNA) and glycyglycine was used as its substrate. CSGT was stable from pH 8.0 to 11.0 and at or below 20℃. It was optimally active at pH 9.0~10.0 and 30℃. A series of reducing reagents could activate CSGT, and metal cations such as Zn2+, Cu2+, Hg2+ , Mn2+ inhibited strongly activity of the enzyme, but K+, Ca2+, Mg2+ and Na+ at high concentrations had no effect on its activity, indicating that its active center could contain -SH.
2.Molecular docking of epidermal growth factor receptor tyramine kinase domain and its inhibitor genistein.
Jianglan YUAN ; Hui LIU ; Xu KANG ; Guolin ZOU
Chinese Journal of Biotechnology 2008;24(10):1813-1817
Genistein is a high specific and noncompetitive inhibitor of epidermal growth factor receptor tyramine kinase domain (EGFR-TK). In the paper, a molecular docking between genistein and EGFR-TK was studied to explore the mechanism of their interaction and antitumor mechanism of genistein by AUTODOCK 3.05 program. The results indicated that genistein located in the active cavity of EGFR-TK by high affinity (deltaG = -31.2 kJ/mol), and genistein inhibited EGFR-TK by interfering with forming of Lys721/Glu738 ion pair. The inhibition belonged to noncompetitive interaction, in which hydrophobic force and hydrogen bond played key roles.
Catalytic Domain
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Genistein
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metabolism
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pharmacology
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Models, Molecular
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Receptor, Epidermal Growth Factor
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antagonists & inhibitors
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metabolism