PROTEOMICS: Taking Over Where Genomics Leaves Off

With the Human Genome Project rapidly approaching closure, researchers are turning increasingly to the task of converting the soon to be completed DNA sequence into information that will potentially improve—and perhaps even revolutionize—human medicine and health care. One of the key challenges ahead: understanding proteomics, the science of the cellular protein universe. Proteomics, in a sense, is more complex than genomics, not only because there are so many possible interactions among proteins, but because there are so many more proteins than genes. Messenger RNAs—transcripts of genomic DNA that directly encode proteins—can be assembled in many different ways. And expressed proteins are typically modified in a variety of ways, such as by phosphorylation and glycosylation. So organisms may have well over an order of magnitude more proteins than genes. Proteomics attempts to catalog and characterize these proteins, compare variations in their expression levels under different conditions (notably sickness versus health), study their interactions, and identify ...