共查询到20条相似文献,搜索用时 15 毫秒
1.
Determination of the amino acid sequence of cystine-containing peptides by tandem mass spectrometry.
D Despeyroux J Bordas-Nagy K R Jennings 《Rapid communications in mass spectrometry : RCM》1991,5(4):156-159
A method has been developed for the determination of the amino-acid sequence of a cyclic peptide containing cystine. It is based on the reduction of the peptide in a reductive matrix prior to ionization by fast-atom bombardment. The amino-acid sequence of the resulting linear peptide is then determined by tandem mass spectrometry from the spectrum produced by the collision-induced decomposition of the [M + H]+ ion of the peptide. 相似文献
2.
Hideki Kambara Shinzaburo Hishida Hiroshi Naganawa 《Journal of mass spectrometry : JMS》1982,17(2):67-73
Secondary ion mass spectrometry for oligopeptides, such as tri-tetra-, penta- and hexapeptides, and bioactive peptides, are presented. Quasimolecular ions and cationized molecules were observed, together with many kinds of fragments, which were helpful in structural assignments. Secondary ion mass spectrometry did not prove to be dependent on temperature. Thermal migration of samples on a surface was observed at high temperature. Secondary ion mass spectra obtained with a silver substrate and an aluminium substrate are compared. 相似文献
3.
The isobutane chemical ionization mass spectra of trimethylsilylated amino acids and oligopeptides are discussed. 相似文献
4.
MS-Pep: a computer program for the interpretation of mass spectra of peptide libraries 总被引:1,自引:0,他引:1
S. Kienle K.-H. Wiesmüller J. Brünjes J. W. Metzger G. Jung 《Fresenius' Journal of Analytical Chemistry》1997,359(1):10-14
Electrospray mass spectrometry (ESI-MS) is an established method for the qualitative analysis of synthetic peptide libraries
and combinatorial mixtures or collections of small organic compounds. However, the calculation of the mass distribution of
even small peptide mixtures is a time-consuming and error-proned task. Therefore, the computer program MS-Pep has been developed,
which calculates the masses of expected peptides, byproducts and the mass distributions of peptide libraries.
Received: 2 December 1996 / Revised: 17 April 1997 / Accepted: 21 April 1997 相似文献
5.
S. Kienle K.-H. Wiesmüller J. Brünjes J. W. Metzger G. Jung 《Analytical and bioanalytical chemistry》1997,359(1):10-14
Electrospray mass spectrometry (ESI-MS) is an established method for the qualitative analysis of synthetic peptide libraries and combinatorial mixtures or collections of small organic compounds. However, the calculation of the mass distribution of even small peptide mixtures is a time-consuming and error-proned task. Therefore, the computer program MS-Pep has been developed, which calculates the masses of expected peptides, byproducts and the mass distributions of peptide libraries. 相似文献
6.
R. Venkataraghavan F. W. McLafferty G. E. van Lear 《Journal of mass spectrometry : JMS》1969,2(1):1-15
A system is described in which computer techniques are used to carry out major steps in the procedure for interpretation of high-resolution mass spectral data. These steps include identification and evaluation of the molecular ion, neutral fragments lost from the molecular ion, and characteristic ion series, followed by elucidation of specific structural details using a sub-routine for the particular compound class selected. The technique shows promise of not only increasing the interpreter's efficiency, but of providing more specific and detailed structural information from the spectral data. 相似文献
7.
Fu H Xu L Lv Q Wang JZ Xiao HZ Zhao YF 《Rapid communications in mass spectrometry : RCM》2000,14(19):1813-1822
Amino acid phosphoramidates of adenosine were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). The fragmentation pathways were investigated. In the positive ion mass spectra abundant characteristic fragment ions appeared, and many complementary ions were found. In the negative ion mass spectra only a few fragment ions were observed, and most of them contained phosphoryl groups. The results show that ESI-MS is a useful tool for structural determination of amino acid phosphoramidates of nucleosides. 相似文献
8.
A. G. Harrison 《Journal of mass spectrometry : JMS》1970,3(5):549-555
The mass spectra of the C3 to C9 n-alkanals and a number of branched aldehydes have been obtained at a resolution sufficient to resolve the O? CH4 doublets. From the resolved spectra, a study of metastable transitions, and the spectrum of one deuterium-labelled alkanal, (n-hexanal-2,2-d2) the major fragmentation reactions have been elucidated. Of particular interest are the γ-cleavage reaction, leading to [C3H5O]+ in the n-alkanals, which proceeds both by a simple cleavage and by cleavage preceded by hydrogen interchange, and the loss of C2H4, which involves loss of the C2 and, probably C3, carbons. 相似文献
9.
É. Kh. Timbekov A. K. Kasimov D. A. Abdullaeva M. K. Yusupov Kh. A. Aslanov 《Chemistry of Natural Compounds》1976,12(3):289-293
On the basis of a mass-spectrometric analysis of regelamine and the products of its reductive decomposition information has
been obtained which confirms the position of the hemiacetal group and its structure as a whole, which is also confirmed by
the results of the mass spectroscopy of the products of the reduction of iolantamine. 相似文献
10.
The increasing importance of spectroscopic methods as an analytical tool in industry, combined with the trend to automatize spectrometers, demands new standards in the quantity and quality of spectrum interpretation. Suitable computer programs should be able to predict structural features from mass spectral properties. The knowledge base is a structure-oriented mass spectral data collection consisting of some 42000 spectra and topologies. The comparison of selected mass spectral properties such as similarity, neutral losses and ion series of the unknown with the equivalent properties of the library spectra results in a set of corresponding structures. Subsequent substructure analysis yields a histogram of substructure frequencies containing information about their statistical relevance. The relevant substructure set may be recombined to produce a structure proposal, as is demonstrated for 1-acetyl-2-methoxy-4-trimethylsilyioxybenzene. In a second example, the relevant substructures derived by the interpretation system are used as input for the 13C-NMR substructure generator. This procedure reduces the solution space of the structure prediction algorithm considerably. Besides the spectrum interpretation, additional possibilities are available. The substructure search enables us, for example, to look for mass spectrometric reaction centres. Beyond that, substructure analysis is applicable to the determination of structural features typical of certain combinations of neutral losses and/or characteristic fragments. 相似文献
11.
É. Kh. Timbekov A. K. Kasimov D. A. Abdullaeva M. K. Yusupov Kh. A. Aslanov 《Chemistry of Natural Compounds》1977,12(3):289-293
Summary On the basis of a mass-spectrometric analysis of regelamine and the products of its reductive decomposition information has been obtained which confirms the position of the hemiacetal group and its structure as a whole, which is also confirmed by the results of the mass spectroscopy of the products of the reduction of iolantamine.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 328–334, May–June, 1976. 相似文献
12.
13.
Paul O. Danis Francois J. Huby 《Journal of the American Society for Mass Spectrometry》1995,6(11):1112-1118
A computer program called MSCOPOL has been developed to aid in the interpretation of copolymer mass spectra. The program reads the mass spectrum, calculates the most likely monomer masses via correlation or Fourier transform methods, determines possible end group masses based on the monomer masses, and can then search monomer and end group data bases for likely chemical moieties. Refinement of the end group result is possible by calculation of the monomer ratio and degree of polymerization as a function of end group mass. The program is written in Microsoft Visual Basic and runs on an IBM compatible PC. Applications are shown for polystyrene, poly(N-vinyl pyrrolidone/vinyl acetate), and poly(ethylene oxide/propylene oxide). 相似文献
14.
H Reinhard R Lauber U P Schlunegger 《Rapid communications in mass spectrometry : RCM》1989,3(4):95-99
The positive electron ionization and negative chemical ionization mass spectra of 15 different derivatives of the tripeptide Phe-Ala-Leu have been compared. Total ion currents and ion currents of sequence-characterizing ions have been measured and compared. The negative-ion spectra, using 10% carbon dioxide in argon as moderator gas, proved to be simpler and contained more abundant sequence ions than the positive electron ionization spectra. 相似文献
15.
A library search algorithm for the identification of mass spectra is described. The algorithm creates the mass vector of an unknown compound spectrum and sequentially compares it with the library files vector. A measure indicating similarity of compares vectors - similarity index is calculated on the basis of weighted factors of identical elements of both vectors. A diagnosticity of vectors element defined as a function of mass distribution of library file is taken as an important parameter in similarity index calculation. 相似文献
16.
Alina D. Zamfir Dragana Fabris Florina Capitan Cristian Munteanu Željka Vukelić Corina Flangea 《Analytical and bioanalytical chemistry》2013,405(23):7321-7335
In this preliminary investigation, a low-grade astrocytoma (AcT) is investigated by high-resolution (HR) mass spectrometry (MS) aiming at characterization of gangliosides with potential biomarker value. The research was conducted towards a comparative mapping of ganglioside expression in AcT, its surrounding tissue (ST) and a normal control brain tissue (NT). HR MS was conducted in the negative ion mode nanoelectrospray ionization (nanoESI). Fragmentation analysis was carried out by collision-induced dissociation (CID) MS2–MS4. Due to the high resolving power and mass accuracy, by comparative mapping of the ganglioside extracts from AcT, ST and NT, under identical conditions, 37 different species in AcT, 40 in ST and 56 in NT were identified. AcT and ST were found to contain 18 identical ganglioside components. Among all three specimens, ST extract presented the highest levels of sialylation, fucosylation and acetylation, a feature which might be correlated to the tumor expansion in the adjacent brain area. MS mapping indicated also that AcT, ST and NT share one doubly deprotonated molecule at m/z 1063.31, attributable to GT1(d18:1/18:0) or GT1(d18:0/18:1). CID MS2–MS4 on these particular ions detected in AcT and ST provided data supporting GT1c isomer in the investigated astrocytoma tissue. Our results show that HR MS has a remarkable potential in brain cancer research for the determination of tumor-associated markers and for their structural determination. Figure
Ganglioside isomer discrimination in human astrocytoma by Orbitrap multistage MS 相似文献
17.
Theoretical Raman spectra of the complex-forming ionic liquids LaCl3 and ScCl3, derived from molecular dynamics computer simulations, are presented. These simulations, which use polarizable ion interaction models, have previously been shown to predict structural properties in excellent agreement with diffraction experiments. The dependence of the polarizability of the melt on the ionic positions, which determines the Raman spectrum through the time dependence of the polarizability correlation function, is modeled on the basis of ab initio electronic structure calculations carried out on alkali chlorides. New simulation techniques are introduced in order to allow the spectrum to be calculated with acceptable statistics. The calculated spectra are in semiquantitative agreement with experimental data. The distinctive bands which appear in the spectra of such complex melts are linked to the vibrations of the transient coordination complexes which form in these melts and new interpretations for the origin of several well-known features are proposed. The simulations thus enable a link between the structure of a melt as perceived through Raman spectroscopy and through diffraction experiments to be made. 相似文献
18.
Tanaka K Takenaka S Tsuyama S Wada Y 《Journal of the American Society for Mass Spectrometry》2006,17(4):508-513
Peptide mass mapping plays a central role in the structural characterization of protein variants with single amino acid substitutions. Among the 20 standard amino acids found in living organisms, 18, all but Leu and Ile, differ from each other in molecular mass. The mass differences between amino acids range from 0.0364 to 129.0578 Da. The mass of the mutated peptide or the difference between normal and mutated peptides uniquely determines the type of substitution in some cases, and even pinpoints the position of the mutation when the involved residue is found only once in the peptide. Among 75 pairs of amino acid residues that are exchangeable via a single nucleotide replacement, 53 show specific change in exact mass, while only 25 in nominal mass. On the other hand, precise measurement, at least to the third decimal place, greatly enhances the capacity of the peptide mass mapping strategy for structural characterization. This notion was verified by an analysis of three Hb variants using MALDI-FTICR MS. In addition, the baseline resolution of two 1 kDa peptides with a single amino acid difference, Lys or Gln, which have the smallest (0.0364 Da) difference among residues, was achieved by measurement at a mass resolving power of 342,000. The results indicated that the smallest difference, 0.0040 Da between [Delta29.9742 for Glu-Val] and [Delta29.9782 for Trp-Arg], among all types of amino acid substitutions derived from a single nucleotide replacement can be discriminated at the present performance level. Therefore, FTICR MS is capable of identifying all 53 types of substitutions, each of which is associated with a unique mass difference, except for the Leu and Ile isomers. 相似文献
19.
Summary Benzophenones have been described to undergo characteristic -cleavage and rearrangement processes upon mass spectrometric fragmentation. Recently two series of new and isomeric benzophenones have been prepared from phenylbenzoates by Fries rearrangement or directly by Friedel Crafts acylation. It is shown that the above mentioned diagnostic fragmentation processes can be used to characterize the resulting isomeric ortho or para hydroxy and ortho or para methoxy benzophenones unambigously.
Charakterisierung von isomeren Benzophenonen durch ihre Massenspektren
Zusammenfassung Von einigen Benzophenonen ist bekannt, daß sie im Massenspektrometer durch charakteristische -Spaltungen und Umlagerungen fragmentiert werden.Durch Friedel-Crafts-Acylierung und Fries'sche Verschiebung wurden kürzlich zwei Serien von neuen und isomeren Benzophenonen hergestellt, an denen gezeigt wird, daß sich die oben genannten diagnostischen Fragmentierungsreaktionen zur Identifizierung der entstehenden isomeren orthooder para-Hydroxy- und ortho-o-der para-Methoxybenzophenone heranziehen lassen.相似文献
20.
An algorithm of the AELITA program (Atomic-Element Identification) is described which enables both low and high resulution mass spectra to be processed to give the elemental composition and ion abundances of the mass spectra in monoisotopic form. The program has no limitations in respect of the elemental composition and spectrum complexity. The criterion for the choice of the most probable solution is based either on the accuracy of measurement of the peak abundances and/or the masses. The program is written in ALGOL, run on a BESM-6 computer, and occupies about 19K core memory. 相似文献