Stop proteolysis fast with a ready-to-use protease inhibitor cocktail.

Thermo Scientific Halt Protease Inhibitor Cocktails are ready-to-use concentrated stock solutions of protease inhibitors for addition to samples to prevent proteolytic degradation during cell lysis and protein extraction procedures.

Each 100X liquid cocktail contains optimized concentrations of six broad-spectrum protease inhibitors stabilized in high-quality dimethylsulfoxide (DMSO). The formulation provides nearly complete inhibition of the serine-proteases,cysteine-proteases, aspartic acid-proteases and aminopeptidases thatare typically present in cellular lysate samples. The identity and concentration of each component in the Halt Protease Inhibitor Cocktail is fully disclosed, leaving no uncertainties about variables and compatibility with experiments. Regular and EDTA-free formulations provide for inhibition of metalloproteases and compatibility with 2D electrophoresis, respectively. The stable, concentrated liquid cocktails are more effective and easier to use than traditional tablets. Available in several different package sizes, Halt Protease Inhibitor Cocktails are exceptionally convenient for either small-scale or large-scale needs.

Highlights of Halt Protease Inhibitor Cocktails:

• Better than tablets – the refrigerator-stable, 100X liquid format is more effective and easier to use than traditional tablet products; just pipette exactly the amount you need
• No proprietary ingredients – fully disclosed formulation contains AEBSF, aprotinin, bestatin, E-64, leupeptin and pepstatin A in DMSO
• Multiple package sizes – choose among several package sizes, including single-use microtubes that keep protease inhibitors fresh and reduce the risk of reagent contamination
• Two popular formulations – regular formulation includes a separate vial of EDTA solution for optional metalloprotease inhibition; EDTA-free formulation ensures compatibility with isoelectric focusing
• Lysis buffer compatible – use with Thermo Scientific Pierce Cell Lysis Buffers or nearly any other commercial or homemade detergent-based lysis reagent

Applications for Protease Inhibitor Cocktails:

• Protection of intact, active cellular proteins from degradation by endogenous proteases
• Inhibition of protease activity from lysates produced by a variety of methods including Thermo Scientific Pierce Cell Lysis Reagents, other commercially formulated cell or tissue lysis products, sonication, French press, blender homogenization or repetitive freeze/thaw cycling
• Screening of extracts for proteolytic activity
• The study of proteolysis in the regulation of cellular processes

Product Details:

Halt Protease Inhibitor Cocktails are easy to use. Simply add 10µL of concentrated cocktail per 1mL of lysis buffer to ensure complete protection of the resulting protein extract. Both EDTA and EDTA-free formulations of Halt Protease Inhibitor Cocktails are available in single-use format (24 x 100µL microtubes) and 1mL, 5mL and 10mL package sizes. The single-use format is ideal for small-scale cell lysis experiments, where each 100µL vial provides just what is needed for a 10mL sample and there is no risk of contaminating or degrading remaining aliquots of cocktail. Each microtube in the strip is heat-sealed with a foil that can be easily punctured by a pipette tip for trouble-free access to a precise amount of Halt Protease Inhibitor Cocktail needed for each experiment.

Proteases make up a large category of enzymes, including endopeptidases and exopeptidases, which catalyze the hydrolytic breakdown of proteins into peptides or amino acids in a wide variety of cell and tissue types. Proteases are regulated and compartmentalized in living cells, but cell lysis releases and mixes them with other extracted proteins. Their activity can thus lead to the loss of a large number of valuable proteins, adversely affecting downstream applications. For this reason, it is common practice to spike cell lysis buffers or cell extracts with a cocktails of compounds known to inactivate or inhibit proteases.

Performance comparison of commercial protease inhibitor cocktails and tablets. Using a validated protease assay and 1.0mg/mL of rat pancreas extract, the Thermo Scientific Halt Protease Inhibitor Single-Use Cocktails were tested against other commercially available tablet-format protease inhibitor cocktails under the same conditions. A 1X final concentration of each inhibitor was added. The single-use formulation resulted in ≥97% inhibition compared to ≥59% inhibition for the tablet.

References about Protease Inhibitor Cocktails:

1. Kulakowska-Bodzon, A. et al. (2006). Methods for samples preparation in proteomic research. J. Chrom. B (doi:10.1016/j.jchromb.2006.10.040).
2. North, M.J. (1989). Prevention of unwanted proteolysis in Proteolytic Enzymes: A Practical Approach (Beynon, R.J., Bond, J.S. eds), pp. 105-124, IRL Press, Oxford.
3. Salvensen, G. and Nagase, H. (1989). Inhibition of proteolytic enzymes in Proteolytic Enzymes: A Practical Approach (Beynon, R.J., Bond, J.S. eds). pp. 83-104, IRL Press, Oxford.

Related Resources
Halt Protease Inhibitors FAQ
Protein Methods Library: Protease and Phosphatase Inhibitors

Related Products
Individual Protease Inhibitors (AEBSF, aprotinin, leupeptin, etc.)
Halt Phosphatase Inhibitor Cocktails
Halt Protease and Phosphatase Inhibitor Cocktails
M-PER Mammalian Protein Extraction Reagent
B-PER Protein Extraction Reagents
All Pierce Cell Lysis Solutions