title: Malondialdehyde tagging improves the analysis of arginine oligomers and arginine-containing dendrimers by HPLC-MS.
abstract: The selective modification of arginine residues by malondialdehyde (MDA) was used to improve the mass spectrometric analysis of arginine oligomers (Arg(x), x = 4, 6, 7, 8, 9) and an arginine-containing dendrimeric peptide. MDA tagging significantly increased the hydrophobicity of the arginine side-chain and resulted in improved retention in RP HPLC of the oligoarginines using formic acid as mobile phase additive. This avoided the use of TFA to generate sufficient retention, as TFA was shown to lead to a dramatically reduced sensitivity (up to ten-fold for Arg(8) and Arg(9)) as a result of the strong signal suppression by ion pairing with multiple basic residues. MDA modification of Arg oligomers not only resulted in improved detection sensitivity for most of the peptides studied (e. g., more than six-fold for Arg(7)), but also greatly enhanced the quality of MS/MS spectra, in line with previous results for other peptides. Furthermore, MDA modification helped to identify major side products in a sample of a dendrimeric peptide, a class of peptides that is typically difficult to analyze by MS.
authors.affiliation: Department of Analytical Chemistry and Food Chemistry, University of Vienna, Waehringer Strasse 38, Vienna, Austria.
authors.forename: Lucia
authors.initials: L
authors.lastname: Onofrejova
authors.forename: Alexander
authors.initials: A
authors.lastname: Leitner
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lindner
mesh_terms: D001120:Arginine / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D050091:Dendrimers / Q000032:analysis*; D008315:Malondialdehyde / Q000737:chemistry*; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D016376:Oligonucleotides, Antisense / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D050091:Dendrimers; D016376:Oligonucleotides, Antisense; D008315:Malondialdehyde; D001120:Arginine