Onofrejova Lucia, Leitner Alexander, Lindner Wolfgang
Department of Analytical Chemistry and Food Chemistry, University of Vienna, Waehringer Strasse 38, Vienna, Austria.
J Sep Sci. 2008 Feb;31(3):499-506. doi: 10.1002/jssc.200700485.
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.
利用丙二醛（MDA）对精氨酸残基进行选择性修饰，以改进精氨酸寡聚物（Arg(x)，x = 4、6、7、8、9）和一种含精氨酸的树枝状肽的质谱分析。MDA标记显著增加了精氨酸侧链的疏水性，并使得在以甲酸作为流动相添加剂的反相高效液相色谱（RP HPLC）中，寡聚精氨酸的保留得到改善。这避免了使用三氟乙酸（TFA）来产生足够的保留，因为已表明TFA会由于与多个碱性残基进行离子配对而导致强烈的信号抑制，从而使灵敏度大幅降低（对于Arg(8)和Arg(9)高达10倍）。对Arg寡聚物进行MDA修饰不仅提高了所研究的大多数肽的检测灵敏度（例如，对于Arg(7)提高了6倍以上），而且还极大地提高了串联质谱（MS/MS）谱图的质量，这与之前对其他肽的结果一致。此外，MDA修饰有助于鉴定树枝状肽样品中的主要副产物，树枝状肽是一类通常难以通过质谱分析的肽。
