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- Buijs, Jos, et al.
(författare)
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A new method for the accurate determination of the isotopic state of single amide hydrogens within peptides using Fourier transform ion cyclotron resonance mass spectrometry
- 2000
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Ingår i: Rapid Communications in Mass Spectrometry. - 0951-4198. ; 14:19, s. 1751-1756
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Tidskriftsartikel (refereegranskat)abstract
- A new method is presented to accurately determine the probability of having a deuterium or hydrogen atom on a specific amide position within a peptide after deuterium/hydrogen (D/H) exchange in solution. Amide hydrogen exchange has been proven to be a sensitive probe for studying protein structures and structural dynamics. At the same time, mass spectrometry in combination with physical fragmentation methods is commonly used to sequence proteins based on an amino acid residue specific mass analysis. In the present study it is demonstrated that the isotopic patterns of a series of peptide fragment ions obtained with capillary-skimmer dissociation, as observed with a 9.4 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer, can be used to calculate the isotopic state of specific amide hydrogens. This calculation is based on the experimentally observed isotopic patterns of two consecutive fragments and on the isotopic binomial distributions of the atoms in the residue constituting the difference between these two consecutive fragments. The applicability of the method is demonstrated by following the sequence-specific D/H exchange rate in solution of single amide hydrogens within some peptides.
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- Ramström, Margareta, et al.
(författare)
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A novel mass spectrometric approach to analysis of hormonal peptides in extracts of mouse pancreatic islets
- 2003
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 270:15, s. 3146-3152
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Tidskriftsartikel (refereegranskat)abstract
- Liquid chromatography mass spectrometry (LC-MS) is a valuable tool in the analysis of proteins and peptides. The combination of LC-MS with different fragmentation methods provides sequence information on components in complex mixtures. In this work, on-line packed capillary LC electrospray ionization Fourier transform ion cyclotron resonance MS was combined with two complementary fragmentation techniques, i.e. nozzle-skimmer fragmentation and electron capture dissociation, for the determination of hormonal peptides in an acid ethanol extract of mouse pancreatic islets. The most abundant peptides, those derived from proinsulin and proglucagon, were identified by their masses and additional sequence-tag information established their identities. Interestingly, the experiments demonstrated the presence of truncated C-peptides, des-(25-29)-C-peptide and des-(27-31)-C-peptide. These novel findings clearly illustrate the potential usefulness of the described technique for on-line sequencing and characterization of peptides in tissue extracts.
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