Sodium dodecyl sulfate(SDS) is a powerful solubilizing detergent which is often used during the separation of highly complex protein mixtures by one- or two-dimensional(2D) gel electrophoresis. Matrix-assisted laser d...Sodium dodecyl sulfate(SDS) is a powerful solubilizing detergent which is often used during the separation of highly complex protein mixtures by one- or two-dimensional(2D) gel electrophoresis. Matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS) is a widely used technique for mass spectrometric analysis of some protein molecules compared to other techniques. But the presence of SDS or some salts usually leads to signal deterioration when using MALDI-MS. A method for using nitrocellulose membrane as the solid-phase carrier combined with n-octyl-β-D-glucopyranoside in the matrix highly enhances the sensitivity of the molecular mass determination of lysozyme. This technique has the advantage that the signal-to-noise of the molecular weight profile is improved compared with the mass spectrum and the profile is relatively easy to interpret.展开更多
A liquid-phase isoelectric focusing electrophoresis system(Rotofor) was used as the prefractionation tool for the sample preparation in the MALDI-MS analysis of a protein mixture. Each fraction collected was then dire...A liquid-phase isoelectric focusing electrophoresis system(Rotofor) was used as the prefractionation tool for the sample preparation in the MALDI-MS analysis of a protein mixture. Each fraction collected was then directly subjected to MALDI-TOF-MS analysis. By this approach, we are able to resolve two types of hemoglobins, A and C, which cannot be successfully separated by means of the traditional SDS-PAGE method.展开更多
AIM: To study the characteristics of the four bioactive pure polysaccharides of Panax quiquefolium L. (PPQI 1～4). METHODS: The polysaccharides were extracted with hot water and grade precipitated with ethanol. They w...AIM: To study the characteristics of the four bioactive pure polysaccharides of Panax quiquefolium L. (PPQI 1～4). METHODS: The polysaccharides were extracted with hot water and grade precipitated with ethanol. They were further purified with Sephadex DEAE A50 and Sephadex G200 chromatography. The molecular weights of the polysaccharides were determined with matrix assisted laser desorption/ionization mass spectrometry (MALDI MS). The sugar compositions were analyzed with GC. The linkage positions of the component sugars were determined by methylation and GC MS. RESULTS: The four polysaccharides are all uronic acid containing heteropolysaccharides with the component sugars of arabinose, galactose and glucose in different molar ratios. The uronic acid contents are within 30%～60%. Their molecular weights are in the range of 2×10 4～7×10 4 u. CONCLUSION: The four new bioactive polysaccharides are all uronic acid containing heteropolysaccharides.展开更多
文摘Sodium dodecyl sulfate(SDS) is a powerful solubilizing detergent which is often used during the separation of highly complex protein mixtures by one- or two-dimensional(2D) gel electrophoresis. Matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS) is a widely used technique for mass spectrometric analysis of some protein molecules compared to other techniques. But the presence of SDS or some salts usually leads to signal deterioration when using MALDI-MS. A method for using nitrocellulose membrane as the solid-phase carrier combined with n-octyl-β-D-glucopyranoside in the matrix highly enhances the sensitivity of the molecular mass determination of lysozyme. This technique has the advantage that the signal-to-noise of the molecular weight profile is improved compared with the mass spectrum and the profile is relatively easy to interpret.
文摘A liquid-phase isoelectric focusing electrophoresis system(Rotofor) was used as the prefractionation tool for the sample preparation in the MALDI-MS analysis of a protein mixture. Each fraction collected was then directly subjected to MALDI-TOF-MS analysis. By this approach, we are able to resolve two types of hemoglobins, A and C, which cannot be successfully separated by means of the traditional SDS-PAGE method.
文摘AIM: To study the characteristics of the four bioactive pure polysaccharides of Panax quiquefolium L. (PPQI 1～4). METHODS: The polysaccharides were extracted with hot water and grade precipitated with ethanol. They were further purified with Sephadex DEAE A50 and Sephadex G200 chromatography. The molecular weights of the polysaccharides were determined with matrix assisted laser desorption/ionization mass spectrometry (MALDI MS). The sugar compositions were analyzed with GC. The linkage positions of the component sugars were determined by methylation and GC MS. RESULTS: The four polysaccharides are all uronic acid containing heteropolysaccharides with the component sugars of arabinose, galactose and glucose in different molar ratios. The uronic acid contents are within 30%～60%. Their molecular weights are in the range of 2×10 4～7×10 4 u. CONCLUSION: The four new bioactive polysaccharides are all uronic acid containing heteropolysaccharides.
