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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