UNIT 21.1 Proteases

  1. Alan J. Barrett

Published Online: 1 MAY 2001

DOI: 10.1002/0471140864.ps2101s21

Current Protocols in Protein Science

Current Protocols in Protein Science

How to Cite

Barrett, A. J. 2001. Proteases. Current Protocols in Protein Science. 21:21.1:21.1.1–21.1.12.

Author Information

  1. Babraham Institute, Babraham, Cambridge, United Kingdom

Publication History

  1. Published Online: 1 MAY 2001
  2. Published Print: SEP 2000


The processes of growth and remodeling of cells and tissues in multicellular organisms require the breakdown of old protein molecules, in concert with the synthesis of new ones. For example, many newly-synthesized molecules require proteolytic processing to convert them to biologically active forms. Proteolysis can terminate the activity of a protein—e.g., capsases mediate apoptosis, which is a vital step in the life cycle of the cell. Proteolysis contributes to defense systems too, as the recognition of peptide fragments of foreign proteins triggers the immune response. Proteases are the class of enzymes involved in these important reactions. This unit discusses the general categories of proteases, and sets the stage for addition of overview units on cysteine proteases, aspartic proteases, and metalloproteases, as well as protocol units featuring techniques for analyzing mammalian and yeast proteasomes and protease inhibitors, among other topics.