Quantitative mass spectrometry is often performed using isotopically labeled samples. Although the 4-trimethylammoniumbutyryl (TMAB) labels have many advantages over other isotopic tags, only two forms have previously been synthesized (i.e., a heavy form containing nine deuteriums and a light form without deuterium). In the present report, two additional forms containing three and six deuteriums have been synthesized and tested. These additional isotopic tags perform identically to the previously reported tags; peptides labeled with the new TMAB reagents coelute from reversed-phase HPLC columns with peptides labeled with the lighter and heavier TMAB reagents. Altogether, these four tags allow for multivariate analysis in a single liquid chromatography/mass spectrometry analysis, with each isotopically tagged peptide differing in mass by 3 Da per tag incorporated. The synthetic scheme is described in simple terms so that a biochemist without specific training in organic chemistry can perform the synthesis. The interpretation of tandem mass spectrometry data for the TMAB-labeled peptides is also described in more detail. The additional TMAB isotopic reagents described here, together with the additional description of the synthesis and analysis, should allow these labels to be more widely used for proteomics and peptidomics analyses.
定量质谱分析常采用同位素标记样品来进行。虽然4-三甲基
铵丁酰(TMAB)标签相较于其他同位素标签具有诸多优势,但此前仅合成了两种形式(即含有九个
氘的重形式和不含
氘的轻形式)。在本文中,我们合成了另外两种含有三个和六个
氘的形式,并进行了测试。这些新增的同位素标签与先前报告的标签表现一致;用新TMAB试剂标记的
多肽在与较轻和较重的TMAB试剂标记的
多肽一起通过反相高效
液相色谱柱时,与之共同洗脱。这些四种标签总共使得在单一
液相色谱/质谱分析中进行多变量分析成为可能,每个同位素标记的
多肽因每次加入的标签而质量相差3道尔顿。合成的方案被简化描述,以便没有受过有机
化学专门训练的
生物化学家也能进行合成。对TMAB标记的
多肽的串联质谱数据的解读也进行了更详细的描述。此处所述的额外TMAB同位素试剂,连同合成和分析的额外描述,应能使这些标签更广泛地用于蛋白质组学和肽组学分析。