What is Proteomics?

Proteomics if a field of global study of the expression of genetic information at the protein level (proteome). It also deals with assessment of three-dimensional structure of proteins and their interactions.

 

Human Proteome Organization (HUPO, www.hupo.org) has postulated in 2001 the aims of proteomics in a more precise manner as identification of all proteins coded by human genome (and other genomes, especially those of model organisms) with the subsequent assessment of a) their (protein) expression in different cell types of the organism - expression proteomics, b) protein distribution in subcellular compartments of the organelles, c) post-translational modifications of the proteins, d) protein-protein interactions (b-d constitute the structural proteomics) and e) relation between protein structure and function (functional proteomics). 

The wide range of the definition of proteomics precipitates into an array of distinct sub-specialties, e.g. Clinical proteomics is trying to identify via the analysis of the protein spectrum in the biological samples (urine, saliva, blood) new markers that can be used in future early diagnosis and treatment of a specific disease. The major role in all spheres in early diagnosis and treatment of a given disease is played by bioinformatics (digitalization, 2D picture analysis of the gels, modeling 3D protein structures and the networks of protein interactions, creation, care and development of publicly available databases). One of the interesting proteomic projects is Swedish Human Protein Atlas (http://www.proteinatlas.org/), that groups the information about expression of individual proteins in different tissues but its uniqueness lies in the accompanying archive of immunohistochemically stained samples - at the time of writing of this text, there were more than 400,000 available. Even though it may seem that because of the availability of RNA/cDNA microarray chips for analysis of expression on the level of transcripts there is enough detailed information about the currently ongoing status of expression of genetic information, it is necessary to understand that

1. not all mRNAs will be translated into the protein
2. The level of transcription of specific, protein-coding RNA not always corresponds to the level of expression and moreover, to activity of the coded protein due to many factors (mRNA, RNA splicing, posttranslational protein modifications, etc.)

Similar to other "-omics" the development of proteomics was significantly influenced by the recent developments in technology. The real development of the proteomics started only after the classical method of 2D electrophoresis was joined by "soft" ionization techniques of mass spectrometry. These techniques are performed using matrix assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI).

Source: http://biol.lf1.cuni.cz/ucebnice/en/proteomics.htm