Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/17954
Citations | ||
Scopus | Web of Science® | Altmetric |
---|---|---|
?
|
?
|
Type: | Journal article |
Title: | The fragmentations of [M-H]- anions derived from underivatised peptides. The side-chain loss of H₂S from Cys. A joint experimental and theoretical study |
Other Titles: | The fragmentations of [M-H]- anions derived from underivatised peptides. The side-chain loss of H(2)S from Cys. A joint experimental and theoretical study |
Author: | Bilusich, D. Brinkworth, C. Mc Anoy, A. Bowie, J. |
Citation: | Rapid Communications in Mass Spectrometry, 2003; 17(22):2488-2494 |
Publisher: | John Wiley & Sons Ltd |
Issue Date: | 2003 |
ISSN: | 0951-4198 1097-0231 |
Statement of Responsibility: | Daniel Bilusich, Craig S. Brinkworth, Andrew M. McAnoy, John H. Bowie |
Abstract: | Loss of H2S is the characteristic Cys side-chain fragmentation of the [M-H]- anions of Cys-containing peptides. A combination of experiment and theory suggests that this reaction is initiated from the Cys enolate anion as follows: RNH-(-)C(CH2SH)CONHR' Ø [RNHC(=CH2)CONHR' (HS-)] Ø [RNHC(=CH2)CO-HNR'-H]-+H2S. This process is facile. Calculations at the HF/6-31G(d)//AM1 level of theory indicate that the initial anion needs only > or =20.1 kcal mol(-1) of excess energy to effect loss of H2S. Loss of CH2S is a minor process, RNHCH(CH2SH)CON(-)-R' Ø RNHCH(CH2S-)CONHR' Ø RNH -CHCONHR+CH2S, requiring an excess energy of > or =50.2 kcal mol(-1). When Cys occupies the C-terminal end of a peptide, the major fragmentation from the [M-H]- species involves loss of (H2S+CO2). A deuterium-labelling study suggests that this could either be a charge-remote reaction (a process which occurs remote from and uninfluenced by the charged centre in the molecule), or an anionic reaction initiated from the C-terminal CO2- group. These processes have barriers requiring the starting material to have an excess energy of > or =79.6 (charge-remote) or > or =67.1 (anion-directed) kcal mol(-1), respectively, at the HF/6-31G(d)//AM1 level of theory. The corresponding losses of CH2O and H2O from the [M-H]- anions of Ser-containing peptides require > or =35.6 and > or =44.4 kcal mol(-1) of excess energy (calculated at the AM1 level of theory), explaining why loss of CH2O is the characteristic side-chain loss of Ser in the negative ion mode. |
Keywords: | Hydrogen Sulfide Cysteine Serine Peptides Spectrometry, Mass, Electrospray Ionization Gas Chromatography-Mass Spectrometry |
Description: | The definitive version may be found at www.wiley.com |
DOI: | 10.1002/rcm.1224 |
Published version: | http://www3.interscience.wiley.com/journal/106559527/abstract |
Appears in Collections: | Aurora harvest 6 Chemistry publications |
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.