The ChELSI Institute, Chemical and Biological Engineering, The University of Sheffield, Sheffield, UK.
Anal Bioanal Chem. 2012 Sep;404(4):1011-27. doi: 10.1007/s00216-012-5918-6. Epub 2012 Mar 27.
The iTRAQ (isobaric tags for relative and absolute quantification) technique is widely employed in proteomic workflows requiring relative quantification. Here, we review the iTRAQ literature; in particular, we focus on iTRAQ usage in relation to other commonly used quantitative techniques e.g. stable isotope labelling in culture (SILAC), label-free methods and selected reaction monitoring (SRM). As a result, we identify several issues arising with respect to iTRAQ. Perhaps frustratingly, iTRAQ's attractiveness has been undermined by a number of technical and analytical limitations: it may not be truly quantitative, as the changes in abundance reported will generally be underestimated. We discuss weaknesses and strengths of iTRAQ as a methodology for relative quantification in the light of this and other technical issues. We focus on technical developments targeted at iTRAQ accuracy and precision, use of 4-plex over 8-plex reagents and application of iTRAQ to post-translational modification (PTM) workflows. We also discuss iTRAQ in relation to label-free approaches, to which iTRAQ is losing ground.
iTRAQ（相对和绝对定量的同重同位素标记）技术广泛应用于需要相对定量的蛋白质组学工作流程中。在这里，我们回顾了 iTRAQ 的文献；特别是，我们专注于 iTRAQ 在与其他常用定量技术（例如培养物中的稳定同位素标记（SILAC）、无标记方法和选择反应监测（SRM））的关系中的使用。结果，我们确定了与 iTRAQ 相关的几个问题。也许令人沮丧的是，iTRAQ 的吸引力受到了许多技术和分析限制的削弱：它可能不是真正的定量，因为报告的丰度变化通常会被低估。我们根据这一点和其他技术问题讨论了 iTRAQ 作为相对定量方法的优缺点。我们专注于针对 iTRAQ 准确性和精密度的技术发展、4 重试剂而不是 8 重试剂的使用以及 iTRAQ 在翻译后修饰（PTM）工作流程中的应用。我们还讨论了 iTRAQ 与无标记方法的关系，iTRAQ 在无标记方法方面正在失去优势。
