Protease Inhibitors and Cocktails: Getting Down to the Basics

Question:

Protease Inhibitors and Cocktails: What Are They?

The Protein Man Says:

Protease inhibitors and protease inhibitor cocktails can best be described as biological and/or chemical compounds that bind reversibly or irreversibly with any proteases present in the solution. Since proteases are naturally released following cell or tissue lysis, these compounds are added to the lysate to protect them from being degraded and preserve the nature of the proteins of interest for subsequent experimentations.

Types of Protease Inhibitors

Protease inhibitors are available individually or as concentrated cocktails. Individual protease inhibitors are best used in applications where the protein being purified is a protease and when performing proteolytic assays of already purified proteins. Some of the most common protease inhibitors include AEBSF, aprotinin, chymostatin and PMSF (for serine proteases), E-64 (for cysteine proteases), EDTA/EGTA and phosphoramidon (for metalloproteases), bestatin (for some aminopeptidases), and pepstatin (for aspartic proteases). Leupeptin can be used to inhibit the action of both serine and cysteine proteases while ALLN can be used to inhibit calpain I and II and other neutral cysteine proteases.

Protease inhibitor cocktails, on the other hand, contain multiple protease inhibitors in appropriate relative amounts so they can ideally be used for most protein work. By using cocktails, you don't have to determine which inhibitors to use and the amount needed to get the job done. You also reduce the risk of human and pipetting errors which may seriously compromise the results of your research.

A number of protease inhibitor cocktails can inhibit a wide range of proteases from cell and tissue samples of animal (both mammals and insects), plant, yeast and bacterial origin. Some broad spectrum protease inhibitor cocktails are also compatible with 2D gel electrophoresis and mass spectrometry. You can likewise get protease inhibitor sets which contain 12 ready-to-use inhibitors design your own protease inhibitor cocktails, supplement your existing cocktails and/or screen for specific protease classes.

For more information onprotease inhibitors, please feel free to download our free guide entitled Protease & Phosphatase Inhibitors, Enzymes & Assays.