Proteome/Proteomic analysis definition

In general, MALDI and ESI are of comparable sensitivity (femtomolar to low picomolar levels of peptides/ proteins) however, it is impossible to make definitive comparisons for two reasons. First, there have been, and continue to be, technological advances improving the sensitivity of both techniques whereby, for example, the use of special hydrophobic surfaces on MALDI targets has been matched by the development of nano-ESI. Second, it has been observed that in complex proteomic analyses, perhaps only 30-50% of all proteins are adequately ionized by both ESI and MALDI, with the remainder being best ionized by either ESI or MALDI alone. Thus there is a good case to be made for the use of both techniques in a comprehensive proteomic analysis (Table 5). 

Figure 6. Protocol of proteomic analysis for the definition of drug targets in breast cancer cells.

Le Bihan, T., Robinson, M. D., Stewart, 1. L, and Figeys, D., Definition and characterization of a trypsinosome from specific peptide characteristics by nano-HPLC-MS/MS and in silico analysis of complex protein mixtures. Journal of Proteome Research 3(6), 1138-1148, 2004. 

A wide range of analytical techniques is used in the characterization of recombinant proteins, including proteomics tools. By definition, proteomics is the simultaneous analysis of complex protein mixtures like tissue extracts, cell lysates, subcellular Iractions or biological fluids at a given time and under precisely defined conditions. Therefore, proteomics tools can also be applied to quantify and identify complex mixtures of proteins in a purified biopharmaceutical. Purify analysis occurs at three stages of the production process during the production (in-process controls), at the end of the purification process on the bulk material, and after the final formulation on the finished product. 

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