Swiss-Prot defines proteomics as "the qualitative and quantitative comparison of proteomes under different conditions to further unravel biological processes."
A genome is the collection of all the genes present in a living being. Genomics refers to the field which concerns itself with the study of a genome. The proteome is the collection of all the proteins. Some doing proteomics is doing research on the proteome.
Proteomics is a far more complicated branch of science than genomics. All cell of a species capable of storing DNA carry the same genome. However, the proteome of different cells are completely different. For example, the proteomes of a neuron and a red blood cell in the same organism would have very little similarity. Proteins are functional unit of living being. Obviously, two cell performing completely different tasks would have a completely different set of functional units (proteome).
The complexities and problems involved in proteomics are enormous in comparison with genomic research. The genome gives us the code for making proteins. Then why do we need to study proteins themselves? The answer is that the genome just gives us a list of parts. It does not tell us what the parts do, how they interact, when they are produced and in what quantity.
Unlike differential display-PCR cDNA micro arrays, and serial analysis of gene expression, proteomics techniques directly investigate the functional molecules. Protein abundance often does not correspond to mRNA abundance. Therefore protein quantitation is essential.
Post Translational Modifications (PTM) are ver common in proteins. A PTM can modify both protein function and structure. PTMs cannot be predicted from genetic code. Proteomics is capable of PTM identication and quantitation.
Before a protein can be examined, it must be extracted from tissues, cells, and organelles. It has to be separated and profiled in a manner which would preserve its functional and structural integrity.
Proteomics aims to:
Proteomics research often involves the following steps: