Proteomic analysis quantitative analyses, confidence

It is also of advantage to use a detection method that is both as sensitive and as linear as possible, in order to achieve a quantitative analysis possible and to limit the amount of sample consumed. In this respect, it is important to underscore that the quantitative precision of proteomic analysis is in the range of 10%, which permits the detection of small variations in protein amount with a good statistical confidence (usually twofold differences). 

Various methods were evaluated for the targeted proteomics of human growth hormone (hGH) in human plasma [111]. hGH was spiked in plasma 10-fold above natural level ( 16 pg/pl). Iiutially, the full plasma proteome was reduced, alkylated, and digested prior to LC-MS via DDA on an ion-trap instrument. hGH could be identified from its T, peptide. Next, the plasma proteome was fractionated by RPLC and GE prior to digestion and LC-MS analysis. hGH could be identified with higher confidence. Finally, an LCxLC-MS approach was apphed, which enabled hGH identification from five tryptic peptides. An important conclusion was that hGH could be detected in a complex sample at the low femtomole level among proteins that were 40,000 x more abundant. The results show that a multidimensional approach may be taken for targeted proteomics and quantitative protein bioanalysis. 

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