Labeling analysis of three neuropeptides（Met-enkephalin, Leu-enkephalin, and neurotensin） with 7-methoxycoumarin-3-carboxylic acid N-succinimidyl ester（MCSE） was investigated. The experimental conditions for label...Labeling analysis of three neuropeptides（Met-enkephalin, Leu-enkephalin, and neurotensin） with 7-methoxycoumarin-3-carboxylic acid N-succinimidyl ester（MCSE） was investigated. The experimental conditions for labeling reaction and HPLC analysis of the neuropeptide derivatives were optimized. It was found that the labeling reatction could be achieved at 37 ℃ for one hour in H3BO3-NaCl-Na2B4O7 buffer（pH=8.3） with a labeling ratio of about 80%. The derivative mixture from the three peptides can be separated in a 40 min linear gradient from 60% to 20% of solvent A（100 mmol/L sodium acetate, pH=5.0） and from 40% to 80% of solvent B[60%（volume fraction） acetonitrile in water]. The resulting labeled products were also confirmed by MALDI-TOF-MS analysis. Compared with the native neuropeptides, the resulting labeled products have a longer absorption and fluorescence wavelengths, which is beneficial to the effective elimination of background fluorescence interference from biological matrix.展开更多
The title compound N,N′ ditosyl 3 methoxyimino 1,5 diaza cyclooctane(4) has been prepared by two methods,the reactions of all steps are carried out under very moderate conditions and the overall yield is high.The str...The title compound N,N′ ditosyl 3 methoxyimino 1,5 diaza cyclooctane(4) has been prepared by two methods,the reactions of all steps are carried out under very moderate conditions and the overall yield is high.The structures of the new compounds 2,3,4 are characterized by elemental analysis,IR, 1H NMR and MS spectroscopy.展开更多
The abzyme with deiodinase activity was modified with diethyl pyrocarbonate(DEPC) and carbodiimide(EDC) respectively. The modified abzymes were dialyzed and their activities were compared with that of the native abzym...The abzyme with deiodinase activity was modified with diethyl pyrocarbonate(DEPC) and carbodiimide(EDC) respectively. The modified abzymes were dialyzed and their activities were compared with that of the native abzyme. The results indicate that the histidine residue is one of the essential groups in the abzyme, and the modification causes the catalytic activity a loss of 70%. The modification of the residues containing carboxyl group with EDC leads to a loss of 50% activity, indicating that acid amino residues play important roles in the catalytic reaction.展开更多
文摘Labeling analysis of three neuropeptides（Met-enkephalin, Leu-enkephalin, and neurotensin） with 7-methoxycoumarin-3-carboxylic acid N-succinimidyl ester（MCSE） was investigated. The experimental conditions for labeling reaction and HPLC analysis of the neuropeptide derivatives were optimized. It was found that the labeling reatction could be achieved at 37 ℃ for one hour in H3BO3-NaCl-Na2B4O7 buffer（pH=8.3） with a labeling ratio of about 80%. The derivative mixture from the three peptides can be separated in a 40 min linear gradient from 60% to 20% of solvent A（100 mmol/L sodium acetate, pH=5.0） and from 40% to 80% of solvent B[60%（volume fraction） acetonitrile in water]. The resulting labeled products were also confirmed by MALDI-TOF-MS analysis. Compared with the native neuropeptides, the resulting labeled products have a longer absorption and fluorescence wavelengths, which is beneficial to the effective elimination of background fluorescence interference from biological matrix.
文摘The title compound N,N′ ditosyl 3 methoxyimino 1,5 diaza cyclooctane(4) has been prepared by two methods,the reactions of all steps are carried out under very moderate conditions and the overall yield is high.The structures of the new compounds 2,3,4 are characterized by elemental analysis,IR, 1H NMR and MS spectroscopy.
文摘The abzyme with deiodinase activity was modified with diethyl pyrocarbonate(DEPC) and carbodiimide(EDC) respectively. The modified abzymes were dialyzed and their activities were compared with that of the native abzyme. The results indicate that the histidine residue is one of the essential groups in the abzyme, and the modification causes the catalytic activity a loss of 70%. The modification of the residues containing carboxyl group with EDC leads to a loss of 50% activity, indicating that acid amino residues play important roles in the catalytic reaction.
