Proteomics Center | Introduction to Proteomics

There's little doubt that proteomics -- the study of an organism's complete complement of proteins -- will have great impact in all areas of the life sciences in the years to come. And the reason is clear. "To really understand biological processes, we need to understand how proteins function in and around cells since they are the functioning units," says Hanno Steen, director of the Proteomics Center at Boston Children's Hospital.

The task of studying the proteome has its share of challenges. One involves the sheer number of proteins that need to be identified. The ~20,000 genes in the human genome can code for at least ten times as many proteins; in extreme cases a single gene alone can code for over 1,000. Another challenge is that amino acids -- the base units of proteins -- are so small. Each amino acid is made from anywhere between 7 and 24 atoms. This is far beyond the reach of even the most powerful microscopes.

Which brings us to the subject of the interactive feature.

How are researchers able to determine the sequence of amino acids that make up proteins? One way is by separating the proteins, breaking them up into smaller pieces, and using mass spectrometers to, in effect, "weigh" each amino acid. Each type of amino acid has a unique mass, making identification relatively straightforward. By identifying and sequencing these smaller pieces, researchers can then determine the identity of the protein they make up.

That's obviously a simple explanation of the process. For a more in-depth explanation, check out our Guide to Sequencing and Identifying Proteins.

• A step-by-step explanation of how to identify and sequence proteins using 2-D electrophoresis, mass spectroscopy and informatics. Requires Flash plugin.
• For an explanation of how the genome is decoded, go to NOVA's Sequence for Yourself.

Credits
Writer/Producer: Rick Groleau
Subject Matter Expert: Hanno Steen, PhD
Designer: Peggy Recinos
Developer: Jeffrey Testa

Researchers at Boston Children's Hospital using proteomics:

Rosalyn Adam, PhD
Alan Cantor, MD, PhD
Michaela Fagiolini, PhD
Richard Gregory, PhD
Xi He, PhD
Zhigang He, PhD
Alex Kentsis, MD, PhD
Richard Lee, MD
Marsha Moses, PhD
Keith Solomon, PhD
Hanno Steen, PhD
Judith Steen, PhD
Clifford Woolf, MD, PhD