Aim A capillary zone electrophoretic method (CZE) was used to determine the interactions between natural products and thrombin. Methods Samples containing natural products and thrombin at various ratios were incubat...Aim A capillary zone electrophoretic method (CZE) was used to determine the interactions between natural products and thrombin. Methods Samples containing natural products and thrombin at various ratios were incubated at 25 ℃ and then were separated by CZE with Tris-acetate buffer at pH 7.2. Each run could be accomplished within 5 min. Results In CZE, the peak width broadened due to the affinity interaction between natural products and thrombin. Compared with positive and negative control, the natural products (CB-1, CB-2) from Coreopsis tinctoria Nuttt. interacted with thrombin; CB-3 from Coreopsis tinctoria Nuttt. and HC-1, HC-2, HC-3 from Cistanche deserticola Ma. did not bind to thrombin. Both qualification and quantification characterizations of the binding were determined. Conclusion The established method is capable of sensitive and fast determination of natural products and thrombin interactions, it can be employed as an alternative method.展开更多
The chlorpheniramine enantiomers were separated with capillary zone electrophoresis using β-cyclodextrin as the chiral selector.The effects of the concentration of β-cyclodextrin, the electrolyte pH and organic modi...The chlorpheniramine enantiomers were separated with capillary zone electrophoresis using β-cyclodextrin as the chiral selector.The effects of the concentration of β-cyclodextrin, the electrolyte pH and organic modifier(urea) on the difference in apparent electrophoretic mobilities of the enantiomels were investigated.展开更多
Aim To strdy the separation of native amino acids using capillary zone electro- pboresis (CZE) with indirect ultraviolet detecition. Methods 13 native amino acids were sepa- rated by capillary electrophoresis with ind...Aim To strdy the separation of native amino acids using capillary zone electro- pboresis (CZE) with indirect ultraviolet detecition. Methods 13 native amino acids were sepa- rated by capillary electrophoresis with indirect detection . The experiments were carried out with homemade CE apparatus under the following operating conditior conditions: a fused-silica capillary col- umn of 50.0cm effect length and of 75m i.d. was used. 7 organic acids were used as BGAE, and a positive potential of separation in CZE with indirect detection. After optimizing for l3 native amino acids were established. Conclusion The choice of BGAe is an important factor influencing the efficiency of separation in CZE with indiect detection .After optimizing the separation conditions a baseline separation for 13 native amino acids is obtained.展开更多
A peptides migration model based on the principle of mechanics is presented in capillary zone electrophoresis (CZE). It is shown that the migration that the (tr) is a function of electric (Q), relative molecular mass ...A peptides migration model based on the principle of mechanics is presented in capillary zone electrophoresis (CZE). It is shown that the migration that the (tr) is a function of electric (Q), relative molecular mass (Mr), conformation parameter (Rc) of peptides and electrophoretic condition parameter(A). The conformation parameter is introduced to characterize multifarious shapes owing to the complex conlormation and the various kinds of macromolecules, where Rc≥1/3. The parameters A and Rc can be obtained from experimental data. The times of migration of the nine standard peptides were measured in pH 2.5buffer on different electrophoretic conditions in CZE. The experimental results agreed well with the theoretical prediction.展开更多
Capillary zone electrophoresis has been applied to the analysis of nucleotides. The effects of buffer concentration. pH and other operating conditions on the separation were investigated and optimized. By using the me...Capillary zone electrophoresis has been applied to the analysis of nucleotides. The effects of buffer concentration. pH and other operating conditions on the separation were investigated and optimized. By using the method, separation and identification of nuclotides in swine tissues were completed.展开更多
CC chemokine receptor 4(CCR4) is a G-protein-coupled receptor which plays a pivotal role in allergic inflammation. In the present study, three extracellular loops(EL1-3) of CCR4 were synthesized, and the interacti...CC chemokine receptor 4(CCR4) is a G-protein-coupled receptor which plays a pivotal role in allergic inflammation. In the present study, three extracellular loops(EL1-3) of CCR4 were synthesized, and the interactions between the extracellular loops and compound S009 were investigated using capillary zone electrophoresis(CZE). Both qualitative and quantitative characterizations of the compound-peptide binding were carried out. The experimental data indicated that compound S009 exhibited interactions with EL3, and a binding constant of(12.5±0.19)×10^4 M^-1 was determined using the Scatchard plot. Our study identified the specific domains of CCR4 that could be targeted by small molecules and provided insights for the discovery of novel CCR4 antagonists.展开更多
Mycophenolic acid (MPA), an immunosuppressive drug, was determined in human plasma by a simple capillary zone electrophoresis (CZE) method. A bare fused-silica capillary with an internal diameter (i.d.) of 75/am...Mycophenolic acid (MPA), an immunosuppressive drug, was determined in human plasma by a simple capillary zone electrophoresis (CZE) method. A bare fused-silica capillary with an internal diameter (i.d.) of 75/am and an effective length of 50 cm was used for the separation. A 200 }aL plasma sample was deproteinized with 400 μL acetonitrile, and the supematant was directly injected into the capillary after a water plug at a pressure of 0.5 psi for 10 s. Boric acid (H3BO3, 200 mmol/L) solution adjusted to a pH of 8.60 with 1 mol/L sodium hydroxide (NaOH) solution was selected as the background electrolyte (BGE) through a uniform design. Calibration curve established on each day was linear over the MPA concentration range of 0.625-30.0 Bg/mL in human plasma with the correlation coefficient (r) larger than 0.9997. The limit of detection (LOD) was 0.200 ~tg/mL. Intra- and inter-day precisions at three concentrations within the calibration range were less than 4.45%. Plasma samples collected from 14 renal transplant recipients treated with the prodrug mycophenolate mofetil (MMF) were analyzed successfully by both the developed CZE technique and a validated high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) technique. The mean absolute and relative differences between the concentrations measured by the two methods were -0.17 and -0.20%, respectively. In conclusion, the CZE method described here was validated to be accurate, precise, and economical for the clinical quantification of MPA.展开更多
HIV-1 gains entry into target cells by sequentially interacting with cellular receptors and co-receptors. Both the receptor and co-receptor are recognized by HIV-1 envelope protein gpl20, which plays a key role in the...HIV-1 gains entry into target cells by sequentially interacting with cellular receptors and co-receptors. Both the receptor and co-receptor are recognized by HIV-1 envelope protein gpl20, which plays a key role in the entry process of HIV-1 into cells. The development of new inhibitors is essential since the viral enzyme reverse transcriptase (RT) is one of the first targets of antiretroviral therapy. It has been reported that a variety of natural plants, such as Artemisia rupestris L., have anti-viral pharmacological activity, and they might be the potential inhibitors of RT or V3 loop of gpl20 against HIV-1. RIQRGPGRAFVT1GK (R15K), the relatively conserved region of V3 loop, can be used for binding research. In this work, we analyzed the interactions between different extracts from Artemisia rupestris L. and R15K by affinity capillary electrophoresis (ACE). Moreover, we analyzed the interactions between different extracts from Artemisia rupestris L. and RT by capillary zone electrophoresis (CZE). Our data showed that the chloroform extract ofArtemisia rupestris L. was active among the different plant extracts, which was consistent with previous studies. Taken together, our study provided a rapid screening method to seek anti-HIV ingredients in natural plants' extracts.展开更多
In order to determine the optimal mode of capillary electrophoresis for the impurity control of β-lactam antibiotics, different modes and various electrophoresis conditions for the separation of impurities were compa...In order to determine the optimal mode of capillary electrophoresis for the impurity control of β-lactam antibiotics, different modes and various electrophoresis conditions for the separation of impurities were compared.The results showed that micellar electrokinetic capillary chromatography(MEKC) was the optimal separation mode for the impurity profiling of β-lactam antibiotics.In MEKC,not only the common R and S isomers,Δ-2 andΔ-3 isomers,and Z and E isomers,but also the impurities of β-lactam antibiotics could be well separated compared with the capillary zone electrophoresis.Therefore,MECK is the first choice for the separation of impurities of β-lactam antibiotics with capillary electrophoresis(CE).The optimal separation could be achieved in MEKC by optimizing the pH and the concentrations of buffered saline,micelles and organic solvent(methanol) in running buffer.展开更多
文摘Aim A capillary zone electrophoretic method (CZE) was used to determine the interactions between natural products and thrombin. Methods Samples containing natural products and thrombin at various ratios were incubated at 25 ℃ and then were separated by CZE with Tris-acetate buffer at pH 7.2. Each run could be accomplished within 5 min. Results In CZE, the peak width broadened due to the affinity interaction between natural products and thrombin. Compared with positive and negative control, the natural products (CB-1, CB-2) from Coreopsis tinctoria Nuttt. interacted with thrombin; CB-3 from Coreopsis tinctoria Nuttt. and HC-1, HC-2, HC-3 from Cistanche deserticola Ma. did not bind to thrombin. Both qualification and quantification characterizations of the binding were determined. Conclusion The established method is capable of sensitive and fast determination of natural products and thrombin interactions, it can be employed as an alternative method.
文摘The chlorpheniramine enantiomers were separated with capillary zone electrophoresis using β-cyclodextrin as the chiral selector.The effects of the concentration of β-cyclodextrin, the electrolyte pH and organic modifier(urea) on the difference in apparent electrophoretic mobilities of the enantiomels were investigated.
文摘Aim To strdy the separation of native amino acids using capillary zone electro- pboresis (CZE) with indirect ultraviolet detecition. Methods 13 native amino acids were sepa- rated by capillary electrophoresis with indirect detection . The experiments were carried out with homemade CE apparatus under the following operating conditior conditions: a fused-silica capillary col- umn of 50.0cm effect length and of 75m i.d. was used. 7 organic acids were used as BGAE, and a positive potential of separation in CZE with indirect detection. After optimizing for l3 native amino acids were established. Conclusion The choice of BGAe is an important factor influencing the efficiency of separation in CZE with indiect detection .After optimizing the separation conditions a baseline separation for 13 native amino acids is obtained.
文摘A peptides migration model based on the principle of mechanics is presented in capillary zone electrophoresis (CZE). It is shown that the migration that the (tr) is a function of electric (Q), relative molecular mass (Mr), conformation parameter (Rc) of peptides and electrophoretic condition parameter(A). The conformation parameter is introduced to characterize multifarious shapes owing to the complex conlormation and the various kinds of macromolecules, where Rc≥1/3. The parameters A and Rc can be obtained from experimental data. The times of migration of the nine standard peptides were measured in pH 2.5buffer on different electrophoretic conditions in CZE. The experimental results agreed well with the theoretical prediction.
文摘Capillary zone electrophoresis has been applied to the analysis of nucleotides. The effects of buffer concentration. pH and other operating conditions on the separation were investigated and optimized. By using the method, separation and identification of nuclotides in swine tissues were completed.
基金National Natural Science Foundation(Grant No.81072612,31270915 and 81071749)Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.201 10001110021 and 20120001110001)the Open Foundation of State Key Laboratory of Natural and Biomimetic Drugs(Grant No.K20110109)
文摘CC chemokine receptor 4(CCR4) is a G-protein-coupled receptor which plays a pivotal role in allergic inflammation. In the present study, three extracellular loops(EL1-3) of CCR4 were synthesized, and the interactions between the extracellular loops and compound S009 were investigated using capillary zone electrophoresis(CZE). Both qualitative and quantitative characterizations of the compound-peptide binding were carried out. The experimental data indicated that compound S009 exhibited interactions with EL3, and a binding constant of(12.5±0.19)×10^4 M^-1 was determined using the Scatchard plot. Our study identified the specific domains of CCR4 that could be targeted by small molecules and provided insights for the discovery of novel CCR4 antagonists.
基金Plan of Vitalizing Education Action Geared to the 21st Century(Plan 985)the 1st Phase Fund of Peking University 985 Project.
文摘Mycophenolic acid (MPA), an immunosuppressive drug, was determined in human plasma by a simple capillary zone electrophoresis (CZE) method. A bare fused-silica capillary with an internal diameter (i.d.) of 75/am and an effective length of 50 cm was used for the separation. A 200 }aL plasma sample was deproteinized with 400 μL acetonitrile, and the supematant was directly injected into the capillary after a water plug at a pressure of 0.5 psi for 10 s. Boric acid (H3BO3, 200 mmol/L) solution adjusted to a pH of 8.60 with 1 mol/L sodium hydroxide (NaOH) solution was selected as the background electrolyte (BGE) through a uniform design. Calibration curve established on each day was linear over the MPA concentration range of 0.625-30.0 Bg/mL in human plasma with the correlation coefficient (r) larger than 0.9997. The limit of detection (LOD) was 0.200 ~tg/mL. Intra- and inter-day precisions at three concentrations within the calibration range were less than 4.45%. Plasma samples collected from 14 renal transplant recipients treated with the prodrug mycophenolate mofetil (MMF) were analyzed successfully by both the developed CZE technique and a validated high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) technique. The mean absolute and relative differences between the concentrations measured by the two methods were -0.17 and -0.20%, respectively. In conclusion, the CZE method described here was validated to be accurate, precise, and economical for the clinical quantification of MPA.
基金National Natural Science Foundation(Grant No.81373372)Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20110001110021 and 20130001110059)
文摘HIV-1 gains entry into target cells by sequentially interacting with cellular receptors and co-receptors. Both the receptor and co-receptor are recognized by HIV-1 envelope protein gpl20, which plays a key role in the entry process of HIV-1 into cells. The development of new inhibitors is essential since the viral enzyme reverse transcriptase (RT) is one of the first targets of antiretroviral therapy. It has been reported that a variety of natural plants, such as Artemisia rupestris L., have anti-viral pharmacological activity, and they might be the potential inhibitors of RT or V3 loop of gpl20 against HIV-1. RIQRGPGRAFVT1GK (R15K), the relatively conserved region of V3 loop, can be used for binding research. In this work, we analyzed the interactions between different extracts from Artemisia rupestris L. and R15K by affinity capillary electrophoresis (ACE). Moreover, we analyzed the interactions between different extracts from Artemisia rupestris L. and RT by capillary zone electrophoresis (CZE). Our data showed that the chloroform extract ofArtemisia rupestris L. was active among the different plant extracts, which was consistent with previous studies. Taken together, our study provided a rapid screening method to seek anti-HIV ingredients in natural plants' extracts.
基金National Key New Drug R&D Program Foundation of China(Grant No.2009ZX09313-027)
文摘In order to determine the optimal mode of capillary electrophoresis for the impurity control of β-lactam antibiotics, different modes and various electrophoresis conditions for the separation of impurities were compared.The results showed that micellar electrokinetic capillary chromatography(MEKC) was the optimal separation mode for the impurity profiling of β-lactam antibiotics.In MEKC,not only the common R and S isomers,Δ-2 andΔ-3 isomers,and Z and E isomers,but also the impurities of β-lactam antibiotics could be well separated compared with the capillary zone electrophoresis.Therefore,MECK is the first choice for the separation of impurities of β-lactam antibiotics with capillary electrophoresis(CE).The optimal separation could be achieved in MEKC by optimizing the pH and the concentrations of buffered saline,micelles and organic solvent(methanol) in running buffer.