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1.
CAO Shu-xia LI Hong-wei GUO Yan-chun LIAO Xin-cheng ZHAO Yu-fen 《高等学校化学研究》2006,22(5):598-601
IntroductionPhosphorylation often acts as a molecular switchcontrolling the protein activity in different pathways asin metabolism,signal transduction,cell division,andso on.Therefore,N-phosphoryl amino acids play aspecial and important role in biological… 相似文献
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Xiang Gao Feng Ni Jian Bao Yan Liu Zhen Zhang Pengxiang Xu Yufen Zhao 《Journal of mass spectrometry : JMS》2010,45(7):779-787
The fragmentation reactions of N‐monoalkyloxyphosphoryl amino acids (N‐MAP‐AAs) were studied by electrospray ionization tandem mass spectrometry (ESI‐MS). The sodiated cyclic acylphosphoramidates (CAPAs) were formed through a characteristic pentacoordinate phosphate participated rearrangement reaction in the positive‐ion ESI‐MS/MS and HR‐MS/MS of N‐MAP‐AAs, in which the fragmentation patterns were clearly different from those observed in the corresponding ESI‐MS/MS of N‐dialkyloxyphosphoryl amino acids/peptides and N‐phosphono amino acids. The formation of CAPAs depended on the chemical structures of N‐terminal phosphoryl groups, such as alkyloxy group, negative charge and alkali metal ion. A possible integrated rearrangement mechanism for both P‐N to P‐O phosphoryl group migration and formation of CAPAs was proposed. The fragmentation patterns of CAPAs as novel intermediates in gas phase were also investigated. In addition, it was found that the formation of α‐amino acid CAPAs was more favorable than β‐ or γ‐CAPAs in gas phase, which was consistent with previous solution‐phase experiments. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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HongXiaLIU ShuShengZHANG JianChenZHANG XiaoYANG LingBoQU YuFenZHAO 《中国化学快报》2005,16(5):643-646
The full scan ESI/MS and ESI/MS^2 of N-(O, O-diisopropyl) phosphoryl aromatic amino acids (DIPPAAAs), N-(O, O-diisopropyl) phosphoryl phenylalanine, N-(O, O-diisopropyl)phosphoryl tryptophan and N-(O, O-diisopropyl) phosphoryl tyrosine, were obtained. The specific ions for them were found. Their stability in the LC mobile phase was investigated using developed HPLC/UV/ESI/MS and the results demonstrated that the DIPPAAAs were stable in the mobile phase (5 mmol/L NH4Ac-MeCN (80:20,v/v, pH7.5) within 48 h. 相似文献
4.
Novel steroidal phosphoramidate conjugates of 3'-azido-2',3'-dideoxythymidine(AZT)and amino acid esterswere synthesized and determined by positive and negative ion electrospray ionization mass spectrometry.The MSfragmentation behaviors of the steroidal phosphoramidate conjugates have been investigated in conjunction withtandem mass spectrometry of ESI-MS/MS.There were three characteristic fragment ions in the positive ion ESImass spectra,which were the Na adduct ions with loss of steroidal moiety,amino acid ester moiety from pseudomolecular ion(M Na)~ ,and the phosphoamino acid methyl ester Na adduct ion by α-cleavage of the phosphora-midate respectively.The main fragment ions in negative ion ESI mass spectra were the ion(M-HN_3)~-,the ion(M-AZT-H)~-,and the ion(M-steroidal moiety-H)~- besides the pseudo molecular ion(M-H)~-.Thefragmentation patterns did not depend on the attached amino acid ester moiety. 相似文献
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Characterization of N‐methylated amino acids by GC‐MS after ethyl chloroformate derivatization 下载免费PDF全文
B. Sudarshana Reddy V. Naresh Chary P. Pavankumar S. Prabhakar 《Journal of mass spectrometry : JMS》2016,51(8):638-650
Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α‐amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N‐methyl and N,N‐dimethyl amino acids were synthesized by the methylation of α‐amino acids and characterized by a GC‐MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC‐MS under EI and methane/CI conditions. The EI mass spectra of ethyl chloroformate derivatives of N‐methyl ( 1–18 ) and N,N‐dimethyl amino acids ( 19–35 ) showed abundant [M‐COOC2H5]+ ions. The fragment ions due to loss of C2H4, CO2, (CO2 + C2H4) from [M‐COOC2H5]+ were of structure indicative for 1–18 . The EI spectra of 19–35 showed less number of fragment ions when compared with those of 1–18 . The side chain group (R) caused specific fragment ions characteristic to its structure. The methane/CI spectra of the studied compounds showed [M + H]+ ions to substantiate their molecular weights. The detected EI fragment ions were characteristic of the structure that made easy identification of the studied compounds, including isomeric/isobaric compounds. Fragmentation patterns of the studied compounds ( 1–35 ) were confirmed by high‐resolution mass spectra data and further substantiated by the data obtained from 13C2‐labeled glycines and N‐ethoxycarbonyl methoxy esters. The method was applied to human plasma samples for the identification of amino acids and methylated amino acids. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Pavankumar Pallerla Sudarshana Reddy Bhumireddy Sai Sachin Lingampally Nagarjuna Chary Ragi Prabhakar Sripadi 《Journal of mass spectrometry : JMS》2019,54(9):761-771
Methylation is one of the important posttranslational modifications of biological systems. At the metabolite level, the methylation process is expected to convert bioactive compounds such as amino acids, fatty acids, lipids, sugars, and other organic acids into their methylated forms. A few of the methylated amino acids are identified and have been proved as potential biomarkers for several metabolic disorders by using mass spectrometry–based metabolomics workstation. As it is possible to encounter all the N‐methyl forms of the proteinogenic amino acids in plant/biological systems, it is essential to have analytical data of all N‐methyl amino acids for their detection and identification. In earlier studies, we have reported the ESI‐MS/MS data of all methylated proteinogenic amino acids, except that of mono‐N‐methyl amino acids. In this study, the N‐methyl amino acids of all the amino acids ( 1 ‐ 21 ; including one isomeric pair) were synthesized and characterized by ESI‐MS/MS, LC/MS/MS, and HRMS. These data could be useful for detection and identification of N‐methyl amino acids in biological systems for future metabolomics studies. The MS/MS spectra of [M + H]+ ions of most N‐methyl amino acids showed respective immonium ions by the loss of (H2O, CO). The other most common product ions detected were [MH‐(NH2CH3]+, [MH‐(RH)]+ (where R = side chain group) ions, and the selective structure indicative product ions due to side chain and N‐methyl group. The isomeric/isobaric N‐methyl amino acids could easily be differentiated by their distinct MS/MS spectra. Further, the MS/MS of immonium ions inferred side chain structure and methyl group on α‐nitrogen of the N‐methyl amino acids. 相似文献
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利用电喷雾质谱、荧光、核磁和理论计算研究了ATP与19种氨基酸的弱相互作用.在质谱中发现除甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)外,其它氨基酸均可观测到与ATP因弱相互作用形成的复合物离子.利用不同质谱锥孔电压下复合物稳定性的不同,分析了侧链基团对ATP与19种氨基酸弱相互作用的影响.并利用荧光光谱和核磁共振波谱法研究了芳香性氨基酸与ATP的弱相互作用.结果表明,氨基酸与ATP的弱相互作用强弱顺序为:色氨酸(Trp)>苯丙氨酸(Phe)>具有R‖C-NH2的氨基酸>具有-RCOOH、-R-NH2的氨基酸>具有-RSH、-ROH的氨基酸>R为长链的氨基酸>R为短链的氨基酸.不同官能团的氨基酸与ATP的弱相互作用的模拟计算也证实了此结论,并发现氨基酸的主侧链基团与ATP分子基团间的多个分子间因氢键作用使复合物能稳定存在.这一结果将为预测蛋白与ATP结合位点及研究ATP的识别机理提供依据. 相似文献
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With introduction of a diisopropyloxy phosphoryl group into the N terminal of amino acids,it was found that proton affinity(PA) of amino acid was enhanced in mass spectrometry.Density functional theory calculations showed that the energy for protonation of DIPP-amino acid is lower than that of amino acid,which means PA of DIPP-AA ishigher than that of corresponding amino acid.These results.Coincident with our empirical results.offer a useful interpretation of experimental observations. 相似文献
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研究了N-磷酰化氨基酸与核苷在水溶液中的反应,反应中能够同时生成小肽和小的寡核苷酸;不同的N-磷酰化氨基酸与不同的核苷之间的反应具有一定的选择性。 相似文献
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Characterization of N,N‐dimethyl amino acids by electrospray ionization–tandem mass spectrometry 下载免费PDF全文
V. Naresh Chary B. Sudarshana Reddy Ch. Dinesh Kumar R. Srinivas S. Prabhakar 《Journal of mass spectrometry : JMS》2015,50(5):771-781
Methylation is an essential metabolic process for a number of critical reactions in the body. Methyl groups are involved in the healthy function of the body life processes, by conducting methylation process involving specific enzymes. In these processes, various amino acids are methylated, and the occurrence of methylated amino acids in nature is diverse. Nowadays, mass‐spectrometric‐based identification of small molecules as biomarkers for diseases is a growing research. Although all dimethyl amino acids are metabolically important molecules, mass spectral data are available only for a few of them in the literature. In this study, we report synthesis and characterization of all dimethyl amino acids, by electrospray ionization–tandem mass spectrometry (MS/MS) experiments on protonated molecules. The MS/MS spectra of all the studied dimethyl amino acids showed preliminary loss of H2O + CO to form corresponding immonium ions. The other product ions in the spectra are highly characteristic of the methyl groups on the nitrogen and side chain of the amino acids. The amino acids, which are isomeric and isobaric with the studied dimethyl amino acids, gave distinctive MS/MS spectra. The study also included MS/MS analysis of immonium ions of dimethyl amino acids that provide information on side chain structure, and it is further tested to determine the N‐terminal amino acid of the peptides. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Jiang Y Fu H Xu L Lu Q Wang JZ Zhao YF 《Rapid communications in mass spectrometry : RCM》2000,14(16):1491-1493
The self-assembly products of N-(O,O'-diisopropyl)-L-alpha-amino acids in aqueous media, N-(O,O'-diisopropyl)phosphoryl dipeptides and tripeptides, were identified by electrospray ionization mass spectrometry. A stepwise fragmentation of the [M + H](+) ions from the C-terminus of N-phosphopeptides was observed. Copyright 2000 John Wiley & Sons, Ltd. 相似文献
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Serra VV Domingues MR Faustino MA Domingues P Tomé JP Neves MG Tomé AC Cavaleiro JA Ferrer-Correia AJ 《Rapid communications in mass spectrometry : RCM》2005,19(18):2569-2580
Porphyrin amino acid conjugates with one or two porphyrin units were analyzed by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The ESI-MS spectra of all the porphyrins studied, obtained in positive ion mode, show the presence of the corresponding protonated molecule [M+H]+; ESI-MS spectra of diporphyrinyl compounds also show the doubly charged ions [M+2H]2+. The fragmentations of these ions induced by collision with argon were studied (ESI-MS/MS). ESI-MS/MS gives detailed structural information about the amino acids associated with the porphyrin. Cleavage of the bonds in the vicinity of the porphyrin moiety and those involving the side chain of amino acid residues gives structural information about this type of association. A fragmentation common to all derivatives corresponds to the cleavage of the phenyl-CO bond. The expected cleavage of the amide bond, that links the porphyrin to the amino acid moiety, is a minor fragmentation, which in some cases is even absent. The MS/MS spectra of the monoporphyrinyl derivatives show product ions characteristic of the amino acid linked to the porphyrin; the fragmentation also indicates when the amino acids has a terminal carboxylic group or a terminal ester group. The fragmentations of the diporphyrinyl compounds occur mainly by the cleavage of the spacer, leading, in the case of the doubly charged ions, to predominantly mono-charged ions, indicating a preferential location of the two protons in separated porphyrinic units. 相似文献
14.
Novel phosphoryl derivatization method for peptide sequencing by electrospray ionization mass spectrometry 总被引:1,自引:0,他引:1
Chen J Chen Y Gong P Jiang Y Li YM Zhao YF 《Rapid communications in mass spectrometry : RCM》2002,16(6):531-536
A one-step phosphoryl derivatization method has been used in a peptide sequencing procedure for electrospray ionization tandem mass spectrometry (ESI-MS/MS). The sodiated derivatized peptides exhibit very simple dissociation patterns, in which two kinds of fragment ions, [b(n) + OH + Na]+ and [a(n) + Na]+, are formed. Since the amino acid residues are lost sequentially from the C-terminus, peptide sequences can be identified easily. The fragmentation efficiency of peptides increased as a result of the phosphorylation, and also provided peaks of useful intensity at lower m/z. A peptide with lysine at the C-terminus was derivatized and analyzed by ESI-MS/MS. Similar mass spectra, from which the sequence could be read out, were obtained. This is a novel derivatization method yielding neutral derivatives that should be suitable for peptide sequencing by LC/ESI-MS/MS. 相似文献
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Gang Li Zhongbin Huang Chuan Fu Pengxiang Xu Yan Liu Yu‐fen Zhao 《Journal of mass spectrometry : JMS》2010,45(6):643-650
The binary mixtures of 7 hexoses and 20 amino acids were investigated by electrospray ionization ion trap mass spectrometry (ESI‐ITMS). The adduct ions of the amino acid and the hexose were detected for 12 amino acids but not for the other 8 amino acids which are basic acidic amino acids and amides. The ions of amino acid–hexose complexes were further investigated by tandem mass spectrometry (MS/MS), and some of them just split easily into two parts whereas the others gave rich fragmentation, such as the complex ions of isoleucine, phenylalanie, tyrosine, and valine. We found that hexoses could be complexed by two molecules of valine but only by one molecule of the other amino acids. Among seven kinds of valine–hexose complexes coordinated by potassium ion, the MS2 spectra of the ion at m/z 453 yielded unambiguous differentiation. And the fragmentation ions are sensitive to the stereochemical differences at the carbon‐4 of hexoses in the complexes, as proved by the MS2. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
17.
The analytical potential of furan as a chemical ionization (CI) reagent was evaluated for selectivity with nine monosubstituted naphthalene compounds. The ion-molecule reactions of furan and tetrahydrofuran (THF) were compared with those of methane, methanol and acetonitrile (prominently producing [M + H](+) ion base peaks) with naphthalene compounds in chemical ionization mass spectrometry (CI-MS). Reactions with furan predominantly show M(+) and [M + 39](+) ions. Based on this phenomenon, investigations were carried out for some of the molecular factors such as proton affinity, substituent effects and the preferred site of [C(3)H(3)](+) ion attachment that influence reactivity in furan CI. High selectivity with different substituents is observed in the formation of [M + 39](+) adduct ion, suggesting its usefulness as selective ionization reagent liquid. The selectivity and sensitivity are illustrated in the analysis of mixture of amino acids. Furthermore, the structure determination and reaction mechanism study is characterized by collision-activated dissociation experiments in CI-MS/MS and CI-MS/MS/MS. 相似文献
18.
Analyses by flow injection as well as liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) were performed with four 4-phenoxyphenol derivatives. When ambient temperature nitrogen gas was used to facilitate solvent evaporation, [M + H]+, [M + NH4]+, and [2M + NH4]+ ions were observed as the major ions. As the nitrogen gas temperature increased from ambient to 250 and 450 degrees C, [M]+*, [M - 1]+ and [M + 15]+ ions were the predominant ions. Heat-induced oxidation was found to be the primary source for the formation of oxidative species. Aqueous solvents were found to be essential for the formation of the [M + 15]+ ions. The [M]+* and [M + 15]+ ions were further characterized by tandem mass spectrometry. Based on the MS/MS data, it was proposed that the [M + 15]+ ions were the in-source generated 1,2-quinone ions. 相似文献
19.
Gao X Zeng Z Xu P Tang G Liu Y Zhao Y 《Rapid communications in mass spectrometry : RCM》2011,25(2):291-300
The isomeric α-amino acyl adenylates and amino acid phosphoramidates of adenosine were synthesized and analyzed in detail by electrospray ionization tandem mass spectrometry (ESI-MS(n)). In ESI-MS/MS of α-amino acyl adenylates, the novel rearrangement ion [cAMP-H](-) observed as the most intense signal was formed through the pentacoordinate phosphorus intermediate with a six-membered ring by nucleophilic attack of the 3'-hydroxyl group on the phosphorus atom. In contrast, for the amino acid phosphoramidate of adenosine, the phosphorus atom could be attacked not only by the carboxylic group to form the cyclic aminoacyl phosphoramidates (CAPAs), but also by the nitrogen atom on the nucleobase leading to intramolecular phosphoryl group migration. It was found that the sodium ion having multidentate binding ability played an essential role in this characteristic rearrangement. The proposed mechanisms were supported by the MS/MS study, deuterium-labeled experiments, high-resolution tandem mass spectrometry and moderate calculations at the B3LYP/6-31G* level. The characteristic fragmentation patterns of α-amino acyl phosphates and amino acid phosphoramidates allows identification of stereoisomers when either the phosphorylation is at the N-terminus or C-terminus of amino acids. 相似文献
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在无机磷试剂辅助下建立了氨基酸自组装成均环肽的方法, 得到了相应的均环肽库. 均环肽库的建立增加了肽库的多样性, 为药物筛选提供了新的选择性. 采用电喷雾多级质谱技术, 对系列均环多肽 [M+H]+离子和[M+Na]+离子的质谱裂解规律进行了系统研究, 两种系列的离子具有不同的质谱裂解特征, 分别提出了其可能的质谱裂解机制. 该研究丰富了环多肽化合物的电喷雾多级质谱研究, 结果表明环肽化合物的加钠离子较加氢离子的质谱图可以更容易地用于环多肽的序列测定. 本研究为其它类似环肽化合物结构的分析鉴定及利用电喷雾质谱推测环肽序列提供了有效的质谱方法. 相似文献