Acid-enhanced field desorption mass spectrometry of zwitterions

Keough, T.; DeStefano, Anthony J.

doi:10.1021/ac00224a009

Cited by 43 publications

(14 citation statements)

References 26 publications

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“…Facile loss of neutral phosphate is a characteristic of serine-and threonine-phosphorylated peptides (49). The y 9 , y 10 , y 11 , and y 12 fragment ions also showed quantitative loss of H 3 PO 4 . The y 11 and y 12 ions showed further loss of NH 3 , as discussed above for tryptic peptides containing a second basic residue.…”

Section: N-terminal Derivatization Methodsmentioning

confidence: 99%

“…Positively charged derivatives have been used in desorption mass spectrometry for many years to improve sensitivity by enhancing ionization efficiencies (11,12). Localization of a positive charge at a particular site on a peptide (13,14) also profoundly affects the nature of the fragment ions observed in high-collision energy tandem mass spectrometry (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26).…”

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confidence: 99%

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A method for high-sensitivity peptide sequencing using postsource decay matrix-assisted laser desorption ionization mass spectrometry

Keough

Youngquist

Lacey

1999

Proc. Natl. Acad. Sci. U.S.A.

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225

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A method has been developed for de novo peptide sequencing using matrix-assisted laser desorption ionization mass spectrometry. This method will facilitate biological studies that require rapid determination of peptide or protein sequences, e.g., determination of posttranslational modifications, identification of active compounds isolated from combinatorial peptide libraries, and the selective identification of proteins as part of proteome studies. The method involves fast, one-step addition of a sulfonic acid group to the N terminus of tryptic peptides followed by acquisition of postsource decay (PSD) fragment ion spectra. The derivatives are designed to promote efficient charge site-initiated fragmentation of the backbone amide bonds and to selectively enhance the detection of a single fragment ion series that contains the C terminus of the molecule (y-ions). The overall method has been applied to pmol quantities of peptides. The resulting PSD fragment ion spectra often exhibit uninterrupted sequences of 20 or more amino acid residues. However, fragmentation efficiency decreases considerably at amide bonds on the C-terminal side of Pro. The spectra are simple enough that de novo sequence tagging is routine. The technique has been successfully applied to peptide mixtures, to high-mass peptides (up to 3,600 Da) and to the unambiguous identification of proteins isolated from two-dimensional gel electrophoresis. The PSD spectra of these derivatized peptides often allow far more selective protein sequence database searches than those obtained from the spectra of native peptides.Knowledge of protein sequences is fundamentally important for understanding many physiological processes at the molecular level (1). Tandem mass spectrometry has become an increasingly essential tool for protein and peptide sequencing because of its speed, sensitivity, and applicability to complex mixtures (2). Recently, postsource decay (PSD) matrix-assisted laser desorption ionization (MALDI) mass spectrometry was developed for high-sensitivity peptide sequencing applications (3-8). Subpicomole limits of analysis were reported as a result of the high yield of fragment ions and the high ion transmission inherent with time-of-flight mass spectrometry (5). Kaufmann et al. (5) also noted several problems associated with PSD MALDI sequencing of peptides, including the complexity of the resulting fragmentation patterns and the lack of computer algorithms capable of interpreting the complex spectra. The recent incorporation of delayed extraction (DE) (9, 10), a technique designed to improve precursor-ion mass resolution and mass-measurement accuracy, reduced the rate of PSD fragmentation by at least an order of magnitude. As a result, many low-intensity precursor ions obtained by DE MALDI do not produce enough PSD fragmentation to allow derivation of even short sequence tags (7).Positively charged derivatives have been used in desorption mass spectrometry for many years to improve sensitivity by enhancing ionization efficiencies (11, 12...

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Section: N-terminal Derivatization Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

A method for high-sensitivity peptide sequencing using postsource decay matrix-assisted laser desorption ionization mass spectrometry

Keough

Youngquist

Lacey

1999

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

225

262

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“…The charge-exchange product ion is of very high abundance for all the phenols studied, being most abundant for o-cresol and p-cresol, which have low ionization energies (8.14 and 8.13 eV)37 compared with that of 2-methoxyethanol(9.6 eV). 37 There are two possible routes to the formation of the most interesting ion for phenols, methyne addition (27) 108 (100) 109 (14) 121 (44) 135 (20) 184 (66) 185 (9) 197 (4) m-Cresol 107 (8) 108 (20) 109 (10) 121 (100) 135 (14) 184 (26) 185 (6) 197 ( [M + 1 + 271' ions indicates that deuterium remains completely in the product ions, i.e. the addition happens on the aromatic ring and the hydroxylic group of phenol remains untouched.…”

Section: Ion-molecule Reactionsmentioning

confidence: 99%

Ion-Molecule Reactions of 2-Methoxyethanol with Ketones, Aldehydes, Alcohols and Phenols under Chemical Ionization Conditions

Pakarinen

Vainiotalo

1996

J. Mass Spectrom.

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“…*' In other cases, stronger acidic agents such as p-toluenesulfonic acid have been found to promote pre-ionization. 30 On the other hand, instances are reported in the literature where analytes in the form of free carboxylic acids have yielded protonated molecular ions without the aid of any pre-ionization promoter^.^' Sample solubility in the liquid matrix is also an important requirement in LSI mass spectrometry. Hence it appears that pre-ionization promoters also impart a simultaneous solubilization, leading to enhanced sensitivity.…”

Section: Positive Ion Spectramentioning

confidence: 99%

Positive and negative liquid secondary ion mass spectrometry of chloro- and nitrophenylglucuronides

Wickramanayake

Deinzer

Burlingame

1985

Biol. Mass Spectrom.

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Mass spectra of a series of chloro- and nitrophenylglucuronides by liquid secondary ion (LSI) mass spectrometry were obtained. In the positive ion mode class characteristic fragmentations and adduct ions are observed only in the presence of alkali salt additives. No additives were necessary in the negative ion mode to see abundant class characteristic [M-H]- and aglycone fragment ions. Cluster ion formation was found to be prominent but only in the negative ion mode.

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Acid-enhanced field desorption mass spectrometry of zwitterions

Cited by 43 publications

References 26 publications

A method for high-sensitivity peptide sequencing using postsource decay matrix-assisted laser desorption ionization mass spectrometry

A method for high-sensitivity peptide sequencing using postsource decay matrix-assisted laser desorption ionization mass spectrometry

Ion-Molecule Reactions of 2-Methoxyethanol with Ketones, Aldehydes, Alcohols and Phenols under Chemical Ionization Conditions

Positive and negative liquid secondary ion mass spectrometry of chloro- and nitrophenylglucuronides

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