巻号一覧
53 巻, 1 号
選択された号の論文の5件中1～5を表示しています
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総合論文
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Yanming AN, Zongming FU, Catherine FENSELAU2005 年 53 巻 1 号 p. 1-6
発行日: 2005年
公開日: 2006/03/01
ジャーナル フリーSolution isoelectrofocusing has been evaluated for prefractionation of nuclear proteins from human cancer MCF-7 cells. Two separation devices were exercised using commercial polyacrylamide membranes, which carry embedded immobiline mixtures to establish pH boundaries between chambers. Protein recovery was quantified and 2-D gel electrophoresis was used to evaluate resolution. Solution isoelectrofocusing provides satisfactory separations and decreases the complexity of the protein mixture, however rates of recovery need to be improved.抄録全体を表示PDF形式でダウンロード (751K) -
Robert J. COTTER, Serguei ILTCHENKO, Dongxia WANG, Rebekah GUNDRY2005 年 53 巻 1 号 p. 7-17
発行日: 2005年
公開日: 2006/03/01
ジャーナル フリーA dual reflectron tandem time-of-flight (TOF/TOF) mass spectrometer reported in 1993 gave rise to the invention and development of the curved-field reflectron (CFR) for focusing product ions. The CFR is used in this case as the second mass analyzer in a tandem instrument (based on the Kratos AXIMA CFR) in which the first mass analyzer is a linear TOF that focuses ions by pulsed extraction. Because ions can be focused over a broad range of kinetic energies, deceleration of precursor ions and/or reacceleration of product ions is not required. Thus, product ions produced by post-source processes (laser induced dissociation or LID, metastable decomposition and opportunistic collisions) are recorded in the product ion mass spectra at the same times as their isomass ions produced by collision induced dissociation (CID). In general both LID and CID product ion mass spectra are very similar, producing primarily b-series and y-series ions, though there is some preference for fragmentation at weaker bonds such as those at proline or aspartic acid residues. The tandem mass spectrometer has been used to determine the acetylation sites for a histone acetyl transferase (HAT) protein. A novel and improved method for derivatizing tryptic fragments by N-terminal sulfonation produces almost exclusively y-series ions, and has been used to determine protein ubiquitination. The tandem mass spectrometer has also been used to identify potential biomarkers associated with heart failure, in particular that fraction containing albumin that is generally removed from serum samples to permit protein biomarker analysis. Analysis of the unfractionated serum, the albuminome, and the depleted serum is also carried out using surface-enhanced laser desorption/ionization (SELDI) and the high molecular weight proteins are monitored by using a Comet macromizerTM TOF mass spectrometer with a very high mass cryocooled detector.抄録全体を表示PDF形式でダウンロード (2518K)
一般論文
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Katsuyoshi MASUDA, Kohichi KAWAHARA, Akihiko KUNIYASU, Masaji ISHIGURO ...2005 年 53 巻 1 号 p. 18-24
発行日: 2005年
公開日: 2006/03/01
ジャーナル フリーUsing mass spectrometry and photoaffinity labeling, we have analyzed the binding of ligands to human serum albumin (HSA). Human serum albumin was selected as the protein, the site photolabeled with the photoaffinity labeling reagent FNAK {(+)-(R)-3,4-dihydro-2-[5-methoxy-2-[3-[N-methyl-N-[2-(3-azidophenoxy)-ethyl]amino]propoxyl]phenyl]-4-methyl-2H-1,4-benzothiazin-3-(4H)-one} was analyzed, and Lys residues at two positions (major: Lys-414 and minor: Lys-541) were found to be the sites photolabeled with FNAK. Based on the results of photolabeling, we proposed a model of the FNAK-HSA complex [K. Kawahara et al., Biochem. J., 363, 223 (2002)]. In this study, for the purpose of clarifying the binding site of the photoaffinity labeling reagent FNAK on HSA molecule, stoichiometry of FNAK in HSA was analyzed in detail by nanoelectrospray ionization mass spectrometry (nanoESI MS), and stoichiometry of FNAK and HSA was found to be 1 : 1. On the basis of these results, a model of HSA-FNAK complex was constructed by the molecular dynamics calculation method. The model strongly suggested that the Myr-3 and Myr-4 binding pockets in subdomain IIIA was the FNAK binding site.抄録全体を表示PDF形式でダウンロード (762K) -
Mayuko ISHIDA, Masayoshi IMAGAWA, Takao SHIMIZU, Ryo TAGUCHI2005 年 53 巻 1 号 p. 25-32
発行日: 2005年
公開日: 2006/03/01
ジャーナル フリーThe various molecular species of lysophosphatidic acid (lysoPA) exhibit different abilities to activate the various lysoPA receptors. The composition of lysoPAs is affected by factors such as external stimulants and diseases and their profile can change on an hourly basis. For this reason, studying lysoPAs or using lysoPAs as markers for the survey of disease requires analysis of individual lysoPA species. We examined methods for sensitive and selective detection of lysoPAs in a mixture of serum lipids using precursor ion scanning and neutral loss scanning. Precursor ion scanning of m/z 153 ([glycerophosphate-H-H2O]-) was effective for first screening of all acyl lysoPAs in lipid mixture due to its high sensitivity. This method has also some advantages such as high selectivity, and rapid and easy operation without conventional method by extraction from thin layer chromatography or separation using high performance liquid chromatography. We successfully detected acyl 22 : 6 (docosahexaenoyl) and 22 : 5 (docosapentaenoyl) lysoPAs in serum using this method.抄録全体を表示PDF形式でダウンロード (447K)
総説
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早川 滋雄, 冠木 伸岳, 川村 義明, 北口 明宏2005 年 53 巻 1 号 p. 33-51
発行日: 2005年
公開日: 2006/03/01
ジャーナル フリーThe most valuable technique for the structure analysis in mass spectrometry, tandem mass spectrometry (MS/MS), involves the excitation of mass-selected species followed by their dissociation into products, the mass-to-charge ratios of which are also measured. Collisionally Activated Dissociation (CAD) has been used as a most common technique to dissociate the mass-selected precursor ions. Charge inversion mass spectrometry is a special branch of MS/MS method, in which the electric charge of the precursor ions is opposite to that of the secondary product ions. Charge inversion mass spectrometry is classified into four types depending on the electric charge and time scales of collisions. Electric charges, which are either positive ions or negative ions, provide the characteristic difference between reactants and products. Either successive single electron transfer in two collisions or double electron transfer in one collision depend time scales of collisions. Charge inversion mass spectrometry using collisions with gaseous targets in the keV collision energy range have provided insights into the structures and reactions of ions and neutral molecules. The characteristics of these four types of charge inversion experiments are presented in terms of the reaction endothermicities, the cross sections and their dependence on the target species. In the case of rare gas or simple molecular targets, double electron transfer in one collision is effective to form positive ions from negative ions, while in the case of alkali metal targets successive single electron transfers in two collisions is effective to form negative ions from positive ions. While CAD is due to dissociation of activated ions with broad internal energy distributions, the charge inversion processes using alkali metal target is due to dissociation of energy-selected neutral species with narrow internal energy distributions.抄録全体を表示PDF形式でダウンロード (1715K)
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