Leitner Alexander, Lindner Wolfgang
Christian Doppler Laboratory for Molecular Recognition Materials, Institute of Analytical Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria.
J Mass Spectrom. 2003 Aug;38(8):891-9. doi: 10.1002/jms.477.
A general labelling method is presented which allows the determination of the number of guanidine groups (related to arginine and homoarginine in peptides and proteins) by means of mass spectrometry. It implies a guanidine-selective derivatization step with 2,3-butanedione and an arylboronic acid under aqueous, alkaline conditions (pH 8-10). The reaction mixture is then directly analysed by electrospray ionization mass spectrometry without further sample pretreatment. Other amino acids are not affected by this reaction although it is demonstrated that lysine side-chains may be unambiguously identified when they are converted to homoarginine prior to derivatization. Guanidine functionalities, as e.g. in the amino acid arginine, are easily identified by the characteristic mass shift between underivatized and derivatized analyte. The tagging procedure is straightforward and selective for guanidine groups. The influence of several experimental parameters, especially the pH of the solution and the choice of reagents, is examined and the method is applied to various arginine-containing peptides and to lysozyme as a representative protein. Possible applications of this technique and its limitations are discussed.
本文提出了一种通用的标记方法，该方法可通过质谱法测定胍基的数量（与肽和蛋白质中的精氨酸和高精氨酸相关）。这意味着在水相碱性条件（pH 8 - 10）下，使用2,3 - 丁二酮和芳基硼酸进行胍基选择性衍生化步骤。然后，反应混合物无需进一步样品预处理即可直接通过电喷雾电离质谱法进行分析。尽管已证明赖氨酸侧链在衍生化之前转化为高精氨酸时可以明确鉴定，但其他氨基酸不受此反应影响。胍基官能团，例如氨基酸精氨酸中的胍基官能团，可通过未衍生化和衍生化分析物之间的特征质量位移轻松鉴定。标记程序简单且对胍基具有选择性。研究了几个实验参数的影响，特别是溶液的pH值和试剂的选择，并将该方法应用于各种含精氨酸的肽以及作为代表性蛋白质的溶菌酶。讨论了该技术的可能应用及其局限性。
