TY - JOUR
T1 - Pyridinium-based ionic liquid matrices can improve the identification of proteins by peptide mass-fingerprint analysis with matrix-assisted laser desorption/ionization mass spectrometry
AU - Zabet-Moghaddam, Masoud
AU - Heinzle, Elmar
AU - Lasaosa, Maria
AU - Tholey, Andreas
N1 - Funding Information:
Acknowledgement This work was supported by the “Bundesmin-isterium für Bildung und Forschung (BMBF)” within the joint project “Biokatalyse in ionischen Flüssigkeiten”.
PY - 2006/1
Y1 - 2006/1
N2 - Matrix-assisted laser desorption/ionization mass spectrometry has become an indispensable tool for identification of proteins by peptide mass-fingerprint analysis. Selection of the matrix, addition of matrix additives, and sample-preparation techniques are known to affect the quality of the spectra and hence protein identification. We investigated the effect of pyridine as matrix additive for the commonly used crystalline matrix α-cyano-4- hydroxycinnamic acid (CCA), forming a pyridinium based ionic liquid matrix, on the mass spectra of synthetic peptides and tryptic protein digests. Beside the equimolar mixture of CCA and pyridine, the effect of addition of substoichiometric amounts of the base to the acid was tested. Optimum results in terms of signal-to-noise ratios, reduction of chemical noise, and reduced formation of alkali adducts and matrix clusters were observed for the matrix CCA-pyridine in the molar ratio 2:1. The optimized ionic liquid matrix was used for identification of tryptic digests of six model proteins and for identification of a protein extracted from a two-dimensional gel with the proteome of the bacterium Corynebacterium glutamicum, and shown to facilitate protein identification, yielding higher scores and increased sequence coverage compared with pure CCA. Thus CCA-Py 2:1 is a potential alternative for identification and characterization of proteins by peptide mass-fingerprint analysis.
AB - Matrix-assisted laser desorption/ionization mass spectrometry has become an indispensable tool for identification of proteins by peptide mass-fingerprint analysis. Selection of the matrix, addition of matrix additives, and sample-preparation techniques are known to affect the quality of the spectra and hence protein identification. We investigated the effect of pyridine as matrix additive for the commonly used crystalline matrix α-cyano-4- hydroxycinnamic acid (CCA), forming a pyridinium based ionic liquid matrix, on the mass spectra of synthetic peptides and tryptic protein digests. Beside the equimolar mixture of CCA and pyridine, the effect of addition of substoichiometric amounts of the base to the acid was tested. Optimum results in terms of signal-to-noise ratios, reduction of chemical noise, and reduced formation of alkali adducts and matrix clusters were observed for the matrix CCA-pyridine in the molar ratio 2:1. The optimized ionic liquid matrix was used for identification of tryptic digests of six model proteins and for identification of a protein extracted from a two-dimensional gel with the proteome of the bacterium Corynebacterium glutamicum, and shown to facilitate protein identification, yielding higher scores and increased sequence coverage compared with pure CCA. Thus CCA-Py 2:1 is a potential alternative for identification and characterization of proteins by peptide mass-fingerprint analysis.
KW - Ionic liquid matrices
KW - Limit of detection
KW - Mass spectrometry
KW - Matrix additives
KW - Proteomics
UR - http://www.scopus.com/inward/record.url?scp=29144532475&partnerID=8YFLogxK
U2 - 10.1007/s00216-005-0130-6
DO - 10.1007/s00216-005-0130-6
M3 - Article
C2 - 16252087
AN - SCOPUS:29144532475
VL - 384
SP - 215
EP - 224
JO - Analytical and Bioanalytical Chemistry
JF - Analytical and Bioanalytical Chemistry
SN - 1618-2642
IS - 1
ER -