Two kinds of saponins have been investigated by negative electrospray ionization(NESI) mass spectrometry. Under ESI conditions, the - ions of saponins were observed which provide the molecular weights of saponins. The...Two kinds of saponins have been investigated by negative electrospray ionization(NESI) mass spectrometry. Under ESI conditions, the - ions of saponins were observed which provide the molecular weights of saponins. The fragment pathways of - ions of these two saponins depend on their structures. For steroidic saponins, - ion only produces the fragment ions by the losses of sugar units. For oleanolic saponins, - ion yields the cross ring ions as well as the fragment ions by the losses of sugar units. Moreover, the abundance of the former is higher than that of the latter. The characteristic fragments are used to provide the sequence and some linkage information of sugar moieties of saponins. Especially, their fragment difference strongly depends on the linkage between the aglycone and the sugar moieties.展开更多
Electrospray ionization(ESI) and tandem mass spectrometry have been used to investigate the gas phase interactions of five metal ions and seven dipeptides. For silver ion, two complexes( + and +) were obtained as well...Electrospray ionization(ESI) and tandem mass spectrometry have been used to investigate the gas phase interactions of five metal ions and seven dipeptides. For silver ion, two complexes( + and +) were obtained as well as the one complex ( +) for transition metal ions. Upon collision activation, there is an obvious difference in MS/MS data between metal ion complex and the protonated molecule. The fragment pathway of each complex is related to the structures of dipeptide and the nature of metal ion which suggest that there are several interaction between the metal ions and dipeptides in gas phase.展开更多
Oligodeoxynucleotide from SARS virus was selected and synthesized. Its complexes with alkaloid compounds were investigated by electrospray mass spectrometry. We found that three alkaloid compounds could interact with ...Oligodeoxynucleotide from SARS virus was selected and synthesized. Its complexes with alkaloid compounds were investigated by electrospray mass spectrometry. We found that three alkaloid compounds could interact with the DNA target molecule in five alkaloids analyzed. With increasing molar ratio of the three alkaloid compounds, the complexes between alkaloids and DNA with different stoichiometric ratios were found in their MS spectra. The order of the alkalinity of their gas phase corresponds to that of liquid phase, that is: Palmatine>Jatrorrhizine>Berberin. The relative abundance of these complexes in mass spectra can assess the relative affinities of above three alkaloid compounds with the DNA target molecule. In this paper, the binding sites between jatrorrhizine and DNA was deduced from the interaction experiments of jatrorrhizine with three nucleosides.展开更多
建立了杜仲中京尼平甙酸的硅胶柱色谱分离纯化及反相高效液相色谱/液相色谱-电喷雾质谱/核磁共振(RP-HPLC/LC-E S I-M S/NMR)鉴定方法。杜仲皮经粉碎后,用70%乙醇提取,提取液经减压蒸馏至干,再用甲醇溶解,然后吸附于硅胶上,并以不同体...建立了杜仲中京尼平甙酸的硅胶柱色谱分离纯化及反相高效液相色谱/液相色谱-电喷雾质谱/核磁共振(RP-HPLC/LC-E S I-M S/NMR)鉴定方法。杜仲皮经粉碎后,用70%乙醇提取,提取液经减压蒸馏至干,再用甲醇溶解,然后吸附于硅胶上,并以不同体积比的氯仿-甲醇混合液按洗脱剂的极性由小到大进行洗脱,以RP-HPLC法检测洗脱液中物质的种类和含量。结果表明:洗脱剂为氯仿-甲醇(体积比为8∶1)的洗脱液经分析为单一组分,其保留时间为5.142m in;以对照品京尼平甙酸添加法测定,其峰高增加;相关紫外光谱和红外光谱检测结果与京尼平甙酸对照品基本一致;结合LC-E S I-M S、1H-NMR和13C-NMR等测定,确定该洗脱组分为京尼平甙酸。展开更多
In this paper,the noncovalent interactions between α1-acid glycoprotein（AAG） and the drugs,such as ketoprofen（KP） and anisodine hydrobromide（AN） were studied by using electrospray ion trap mass spectrometry met...In this paper,the noncovalent interactions between α1-acid glycoprotein（AAG） and the drugs,such as ketoprofen（KP） and anisodine hydrobromide（AN） were studied by using electrospray ion trap mass spectrometry method.The results show that both of the drugs had a strong coalescent interaction with AAG,the（dissociation） constants（Kd） and the apparent stoichiometric ratio of noncovalent complexes AN-AAG were（1.75×10-3 mol/L） and 1∶7,and those for KP-AAG complex were 4.95×10-4 mol/L and 1∶4,respectively.According to the thermodynamic parameters of the noncoralent complexes,the main sorts of binding force were static-electricity gravitation for KP-AAG and Van der Waals force for AN-AAG,respectively. The experiment proves that ESI-MS technology as a new method for studying the drug-protein noncoralent binding can offer some advantages in sensitivity,speed,accuracy and directness particularly in the determination of the stoichiormetry of the complex compared to other well-established methods such as circular dichroism and fluorescence spectroscopy,etc.展开更多
文摘Two kinds of saponins have been investigated by negative electrospray ionization(NESI) mass spectrometry. Under ESI conditions, the - ions of saponins were observed which provide the molecular weights of saponins. The fragment pathways of - ions of these two saponins depend on their structures. For steroidic saponins, - ion only produces the fragment ions by the losses of sugar units. For oleanolic saponins, - ion yields the cross ring ions as well as the fragment ions by the losses of sugar units. Moreover, the abundance of the former is higher than that of the latter. The characteristic fragments are used to provide the sequence and some linkage information of sugar moieties of saponins. Especially, their fragment difference strongly depends on the linkage between the aglycone and the sugar moieties.
文摘Electrospray ionization(ESI) and tandem mass spectrometry have been used to investigate the gas phase interactions of five metal ions and seven dipeptides. For silver ion, two complexes( + and +) were obtained as well as the one complex ( +) for transition metal ions. Upon collision activation, there is an obvious difference in MS/MS data between metal ion complex and the protonated molecule. The fragment pathway of each complex is related to the structures of dipeptide and the nature of metal ion which suggest that there are several interaction between the metal ions and dipeptides in gas phase.
文摘Oligodeoxynucleotide from SARS virus was selected and synthesized. Its complexes with alkaloid compounds were investigated by electrospray mass spectrometry. We found that three alkaloid compounds could interact with the DNA target molecule in five alkaloids analyzed. With increasing molar ratio of the three alkaloid compounds, the complexes between alkaloids and DNA with different stoichiometric ratios were found in their MS spectra. The order of the alkalinity of their gas phase corresponds to that of liquid phase, that is: Palmatine>Jatrorrhizine>Berberin. The relative abundance of these complexes in mass spectra can assess the relative affinities of above three alkaloid compounds with the DNA target molecule. In this paper, the binding sites between jatrorrhizine and DNA was deduced from the interaction experiments of jatrorrhizine with three nucleosides.
文摘建立了杜仲中京尼平甙酸的硅胶柱色谱分离纯化及反相高效液相色谱/液相色谱-电喷雾质谱/核磁共振(RP-HPLC/LC-E S I-M S/NMR)鉴定方法。杜仲皮经粉碎后,用70%乙醇提取,提取液经减压蒸馏至干,再用甲醇溶解,然后吸附于硅胶上,并以不同体积比的氯仿-甲醇混合液按洗脱剂的极性由小到大进行洗脱,以RP-HPLC法检测洗脱液中物质的种类和含量。结果表明:洗脱剂为氯仿-甲醇(体积比为8∶1)的洗脱液经分析为单一组分,其保留时间为5.142m in;以对照品京尼平甙酸添加法测定,其峰高增加;相关紫外光谱和红外光谱检测结果与京尼平甙酸对照品基本一致;结合LC-E S I-M S、1H-NMR和13C-NMR等测定,确定该洗脱组分为京尼平甙酸。
文摘In this paper,the noncovalent interactions between α1-acid glycoprotein（AAG） and the drugs,such as ketoprofen（KP） and anisodine hydrobromide（AN） were studied by using electrospray ion trap mass spectrometry method.The results show that both of the drugs had a strong coalescent interaction with AAG,the（dissociation） constants（Kd） and the apparent stoichiometric ratio of noncovalent complexes AN-AAG were（1.75×10-3 mol/L） and 1∶7,and those for KP-AAG complex were 4.95×10-4 mol/L and 1∶4,respectively.According to the thermodynamic parameters of the noncoralent complexes,the main sorts of binding force were static-electricity gravitation for KP-AAG and Van der Waals force for AN-AAG,respectively. The experiment proves that ESI-MS technology as a new method for studying the drug-protein noncoralent binding can offer some advantages in sensitivity,speed,accuracy and directness particularly in the determination of the stoichiormetry of the complex compared to other well-established methods such as circular dichroism and fluorescence spectroscopy,etc.
