With a view to finding out precisely how small peptides recognize a particular binding site of DNA, we have accomplished DNA binding studies of two peptides, H-Tyr-Arg-OH (YR) and H-Gly-Gly-His-OH (GGH) by using measu...With a view to finding out precisely how small peptides recognize a particular binding site of DNA, we have accomplished DNA binding studies of two peptides, H-Tyr-Arg-OH (YR) and H-Gly-Gly-His-OH (GGH) by using measurements in comparison with the binding between DNA and Hoechst 33258. The inhibition mode by YR and GGH to DNA binding of Hoechst 33258 was analyzed by Lineweaver-Burk plot which shows the plot of typical competitive inhibition at concentration of Hoechst 33258 from 3.66 ( 10-9 mol / L to 1.09 ( 10-8 mol / L. And it is concluded that YR binds to DNA in its minor groove (AT rich regions) with a binding constant K = 1.02 ( 108 (mol / L)-1. The GGH(s specificity is reduced at high concentration because it can also bind GC base pair.展开更多
Objective: To reveal the mechanism and effect of SU5416 in the treatment of mouse Lewis cancer in vivo. Methods: Lewis cell was transplanted into groin of C57/B6 mouse by subcutaneous injection, then SU5416 was admini...Objective: To reveal the mechanism and effect of SU5416 in the treatment of mouse Lewis cancer in vivo. Methods: Lewis cell was transplanted into groin of C57/B6 mouse by subcutaneous injection, then SU5416 was administrated intraperitoneally to investigate the impact of SU5416 on tumor angiogenesis and growth in vivo. 32 mice were treated with SU5416 at two different doses every day until the end-point. As a control, 8 mice received no treatment and 8 mice were treated with vehicle (DMSO) only after implantation. Results: Median survival in the treated group was statistically longer compared to that in the control groups (P < 0.05) and no significant systemic adverse was observed. Histological analysis of the treated tumors showed an increase in necroses and reduced in angiogenesis compared to the control tumors. Furthermore, the percent of apoptotic cells increased in the treated tumors by FCM, the expressions of VEGF and KDR had no change after SU5416 administration by western blot. Conclusion: SU5416 may be useful therapeutics drug that specifically inhibits the enzymatic activity of KDR kinase and could down regulate the tumor angiogenesis.展开更多
A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a...A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a-D-glucopyranoside （pAPG）, which may induce aggregation of pAPG-functionalized gold nano- particles （AuNPs） to achieve color change of the test solution. Because pAPG is the substrate of α-glucosidase, the aggregation of AuNPs will be influenced by α-glucosidase since there is no coordination reactivity between PDBA and 4-aminobenzene, the hydrolyzed product of pAPG catalyzed by the enzyme. Therefore, a simple and easily-operated colorimetric method for the assay of a-glucosidase activity can be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 650 nm to that at 520 nm vary linearly with the α-glucosidase activity within a range from 0.05 to 1.1 U/mL with a lowest detection limit of 0.004 U/mL. Moreover, using the proposed method, the inhibition effect of gallic acid and quercetin on a-glucosidase activity can be tested with IC50 values of 1.16 mM and 1.82 μM, respectively. Thus, the method has a great potential not only for the detection of a-glucosidase activity, but also for the screening of its inhibitors.展开更多
文摘With a view to finding out precisely how small peptides recognize a particular binding site of DNA, we have accomplished DNA binding studies of two peptides, H-Tyr-Arg-OH (YR) and H-Gly-Gly-His-OH (GGH) by using measurements in comparison with the binding between DNA and Hoechst 33258. The inhibition mode by YR and GGH to DNA binding of Hoechst 33258 was analyzed by Lineweaver-Burk plot which shows the plot of typical competitive inhibition at concentration of Hoechst 33258 from 3.66 ( 10-9 mol / L to 1.09 ( 10-8 mol / L. And it is concluded that YR binds to DNA in its minor groove (AT rich regions) with a binding constant K = 1.02 ( 108 (mol / L)-1. The GGH(s specificity is reduced at high concentration because it can also bind GC base pair.
基金a grant from the National Key Project of Scientific and Technical Supporting Programs funded by Ministry of Science & Technology of China (No. 2006BAI02A05).
文摘Objective: To reveal the mechanism and effect of SU5416 in the treatment of mouse Lewis cancer in vivo. Methods: Lewis cell was transplanted into groin of C57/B6 mouse by subcutaneous injection, then SU5416 was administrated intraperitoneally to investigate the impact of SU5416 on tumor angiogenesis and growth in vivo. 32 mice were treated with SU5416 at two different doses every day until the end-point. As a control, 8 mice received no treatment and 8 mice were treated with vehicle (DMSO) only after implantation. Results: Median survival in the treated group was statistically longer compared to that in the control groups (P < 0.05) and no significant systemic adverse was observed. Histological analysis of the treated tumors showed an increase in necroses and reduced in angiogenesis compared to the control tumors. Furthermore, the percent of apoptotic cells increased in the treated tumors by FCM, the expressions of VEGF and KDR had no change after SU5416 administration by western blot. Conclusion: SU5416 may be useful therapeutics drug that specifically inhibits the enzymatic activity of KDR kinase and could down regulate the tumor angiogenesis.
文摘A colorimetric method has been established for a-glucosidase activity assay and its inhibitor screening. The method is based on the specific recognition between 1,4-phenylenediboronic acid （PDBA） and 4-aminophenyl-a-D-glucopyranoside （pAPG）, which may induce aggregation of pAPG-functionalized gold nano- particles （AuNPs） to achieve color change of the test solution. Because pAPG is the substrate of α-glucosidase, the aggregation of AuNPs will be influenced by α-glucosidase since there is no coordination reactivity between PDBA and 4-aminobenzene, the hydrolyzed product of pAPG catalyzed by the enzyme. Therefore, a simple and easily-operated colorimetric method for the assay of a-glucosidase activity can be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 650 nm to that at 520 nm vary linearly with the α-glucosidase activity within a range from 0.05 to 1.1 U/mL with a lowest detection limit of 0.004 U/mL. Moreover, using the proposed method, the inhibition effect of gallic acid and quercetin on a-glucosidase activity can be tested with IC50 values of 1.16 mM and 1.82 μM, respectively. Thus, the method has a great potential not only for the detection of a-glucosidase activity, but also for the screening of its inhibitors.
