ABSTRACT
Proteomics is a powerful, still-emerging research technology for qualitative and quantitative comparison of protein composition under different conditions to interrogate biological processes. Although genomics gave rise to the concept of a proteome, the proteome differs conceptually from the genome in several ways beyond the fact that proteins are translated from genes. The proteome has a unique complexity compared with the genome. About 25,000 protein coding-genes have been identified in human but more than 67,000 proteins are derived from these genes because of alternative splicing and protein degradation (IPI human protein database: https://www.ebi.ac.uk/IPI/IPIhuman .html). In addition, more than 100 types of posttranslational modifications
T&F Cat # C6847 Chapter: 14 page: 337 date: August 5, 2009
T&F Cat # C6847 Chapter: 14 page: 338 date: August 5, 2009
(PTMs) can present in the proteome and these are not encoded in the genome. In contrast to the genes, proteins in human proteome exist in a very large concentration range. It is estimated that protein concentration differences range to 107−8-fold in human cells, and to at least 1012-fold in human plasma. Highly abundant proteins dramatically complicate proteome analyses, the 12 most abundant proteins constitute approximately 95% of the total protein mass of human plasma or serum (Anderson and Anderson, 2002). This complicates analysis of the remaining, less abundant proteins. Finally, the human proteome is highly dynamic and subject to large biological variations. A proteome differs from cell to cell and is in a state of constant flux from biochemical interactions with the genome and the environment. One organism has radically different protein expression patterns in different parts of its body, at different stages of its life cycle and in different environmental conditions.
