TY - JOUR
T1 - Peptide peak intensities enhanced by cysteine modifiers and MALDI TOF MS
AU - Zabet-Moghaddam, Masoud
AU - Shaikh, Aarif L.
AU - Niwayama, Satomi
PY - 2012/12
Y1 - 2012/12
N2 - Two cysteine-specific modifiers we reported previously, N-ethyl maleimide (NEM) and iodoacetanilide (IAA), have been applied to the labeling of cysteine residues of peptides for the purpose of examining the enhancement of ionization efficiencies in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). The peak intensities of the peptides as a result of modification with these modifiers were compared with the peak intensities of peptides modified with a commercially available cysteine-specific modifier, iodoacetamide (IA). Our experiments show significant enhancement in the peak intensities of three cysteine-containing synthetic peptides modified with IAA compared to those modified with IA. The results showed a 4.5-6-fold increase as a result of modification with IAA compared to modification with IA. Furthermore, it was found that IAA modification also significantly enhanced the peak intensities of many peptides of a commercially available proteins, bovine serum albumin (BSA), compared to those modified with IA. This significant enhancement helped identify a greater number of peptides of these proteins, leading to a higher sequence coverage with greater confidence scores in identification of proteins with the use of IAA.
AB - Two cysteine-specific modifiers we reported previously, N-ethyl maleimide (NEM) and iodoacetanilide (IAA), have been applied to the labeling of cysteine residues of peptides for the purpose of examining the enhancement of ionization efficiencies in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). The peak intensities of the peptides as a result of modification with these modifiers were compared with the peak intensities of peptides modified with a commercially available cysteine-specific modifier, iodoacetamide (IA). Our experiments show significant enhancement in the peak intensities of three cysteine-containing synthetic peptides modified with IAA compared to those modified with IA. The results showed a 4.5-6-fold increase as a result of modification with IAA compared to modification with IA. Furthermore, it was found that IAA modification also significantly enhanced the peak intensities of many peptides of a commercially available proteins, bovine serum albumin (BSA), compared to those modified with IA. This significant enhancement helped identify a greater number of peptides of these proteins, leading to a higher sequence coverage with greater confidence scores in identification of proteins with the use of IAA.
KW - MALDI TOF
KW - alkylation
KW - cysteine modifier
KW - ionization efficiencies
KW - peak enhancement
UR - http://www.scopus.com/inward/record.url?scp=84871841138&partnerID=8YFLogxK
U2 - 10.1002/jms.3093
DO - 10.1002/jms.3093
M3 - Article
C2 - 23280742
AN - SCOPUS:84871841138
SN - 1076-5174
VL - 47
SP - 1546
EP - 1553
JO - Journal of Mass Spectrometry
JF - Journal of Mass Spectrometry
IS - 12
ER -