In the current omics-age of research, major developments have been made in technologies
that attempt to survey the entire repertoire of genes, transcripts, proteins, and metabolites present
within a cell. While genomics has led to a dramatic increase in our understanding of such
things as disease morphology and how organisms respond to medications, it is critical to obtain information
at the proteome level since proteins carry out most of the functions within the cell. The
primary tool for obtaining proteome-wide information on proteins within the cell is mass spectrometry
(MS). While it has historically been associated with the protein identification, developments
over the past couple of decades have made MS a robust technology for protein quantitation
as well. Identifying quantitative changes in proteomes is complicated by its dynamic nature and the
inability of any technique to guarantee complete coverage of every protein within a proteome sample.
Fortunately, the combined development of sample preparation and MS methods have made it
capable of quantitatively comparing many thousands of proteins obtained from cells and organisms.