Mass spectrometry-based quantitative proteomic profiling.

Quantitative proteomics involves the identification and quantitation of protein components in various biological systems. Stable isotope labelling technology, by both metabolic and chemical methods, has been the most commonly used approach for global proteome-wide profiling. Recently, its capability has been extended from labelled pairs to multiple labels, allowing for the simultaneous quantification of multiplex samples. The ion intensity-based quantitative approach has progressively gained more popularity as mass spectrometry performance has improved significantly. Although some success has been reported, it remains difficult comprehensively to characterise the global proteome, due to its enormous complexity and dynamic range. The use of sub-proteome fractionation techniques permits a simplification of the proteome and provides a practical step towards the ultimate dissection of the entire proteome. Further development of the technology for targeting sub-proteomes on a functional basis - such as selecting proteins with differential expression profiles from mass spectrometric analyses, for further mass spectrometric sequencing in an intelligent manner--is expected in the near future.