Ong Shao-En, Mann Matthias
The Broad Institute of MIT and Harvard, 320 Bent Street, Cambridge, Massachusetts 02141, USA.
Nat Chem Biol. 2005 Oct;1(5):252-62. doi: 10.1038/nchembio736.
The field of proteomics is built on technologies to analyze large numbers of proteins--ideally the entire proteome--in the same experiment. Mass spectrometry (MS) has been successfully used to characterize proteins in complex mixtures, but results so far have largely been qualitative. Two recently developed methodologies offer the opportunity to obtain quantitative proteomic information. Comparing the signals from the same peptide under different conditions yields a rough estimate of relative protein abundance between two proteomes. Alternatively, and more accurately, peptides are labeled with stable isotopes, introducing a predictable mass difference between peptides from two experimental conditions. Stable isotope labels can be incorporated 'post-harvest', by chemical approaches or in live cells through metabolic incorporation. This isotopic handle facilitates direct quantification from the mass spectra. Using these quantitative approaches, precise functional information as well as temporal changes in the proteome can be captured by MS.
蛋白质组学领域建立在能够在同一实验中分析大量蛋白质（理想情况下是整个蛋白质组）的技术之上。质谱分析法（MS）已成功用于鉴定复杂混合物中的蛋白质，但目前的结果大多是定性的。最近开发的两种方法提供了获得定量蛋白质组学信息的机会。比较同一肽段在不同条件下的信号，可以大致估计两个蛋白质组之间蛋白质的相对丰度。或者，更准确的方法是，用稳定同位素标记肽段，使来自两种实验条件下的肽段产生可预测的质量差异。稳定同位素标记可以在“收获”后通过化学方法引入，也可以通过代谢掺入在活细胞中引入。这种同位素标记有助于从质谱图中直接进行定量分析。使用这些定量方法，质谱分析法可以获取蛋白质组的精确功能信息以及随时间的变化情况。
