Gene Expression Analysis : Proteomics

The study of the proteome, or all the proteins expressed by a genome, including their relative abundance, distribution, posttranslational modifications, functions, and interactions with other macromolecules, is known as proteomics. The 20,000–25,000 protein-coding genes of the human genome translate into well over 100,000 proteins when posttranscriptional and posttranslational modifications are considered.
Although a genome remains essentially unchanged, the amounts and types of proteins in any particular cell change dramatically as genes are turned on and off. [Note: Proteomics (and genomics) required the parallel development of bioinformatics, the computer-based organization, storage, and analysis of biologic data.] Figure 1 compares some of the analytic techniques .

Figure 1:  Techniques used to analyze DNA, RNA, and proteins. [Note: The three blotting techniques involve the use of a gel.] ASO = allele-specific oligonucleotides. ELISA = enzyme-linked immunosorbent assay; cDNA = complementary DNA.