Absolute quantitation of peptide/protein using mass spectrometry:Is it a Fact or a Fiction?

Considerable efforts have been made to develop tools for the absolute quantitation of peptide/protein using mass spectrometry (MS). Proteomics researchers are so fascinated with the concept of absolute quantiatation and they are spending enormous amount of time for developing tools or optimizing methods for the absolute quantitation of proteins in a cell or tissue or organ. These experiments and technology development efforts not only take lot of time but also involve huge capital investment. The question is, whether it is worth spending so much money in these efforts? The arguments for justifying such studies are that it is necessary to understand the absolute quantity of a protein for quantitative proteomics. This will enable us to quantitate exact amount of toxins in food/environment, biomarker proteins and drug target proteins and so on. It looks very reasonable to measure the exact quantity of a disease biomarker or Staphylococcal enterotoxins in various foods.

Let us take an example of measuring Staphylococcal toxins in a meat sample. By using expensive isotopically labeled peptides or complex in vivo/in vitro expression system derived proteins/peptides or various software intense label-free methods, we can measure the exact amount of toxins present in the meat sample. Now, we need to see, is there any real practical applications of this information? Do we really need to know the exact concentration of toxins? What are the advantages of this method over antibody based ELISA approaches, which are more frequently used; less expensive and more robust? Read more: http://www.sciclips.com/sciclips/blogMain.do