Protein Stabilization Reagents from Roche

Protect your proteins with Protease and Phosphatase Inhibitor Cocktail tablets

Naturally-occurring proteases and phosphatases can destroy proteins that you spent days isolating. With Roche’s experience in protein isolation, purification, and protein protection against degradation, you can save valuable time and resources purifying intact, high yield, functional protein. Roche’s easy-to-use inhibitor cocktail tablets allow quick and effective inhibition of a wider range of proteases and protein dephosphorylation for a proven no-weighing solution that provides consistent results.

Protease Inhibitor Cocktail Tablets

cOmplete™ Protease Inhibitor Cocktail tablets from Roche inhibit a broad spectrum of serine, cysteine, acid and metalloproteases, as well as calpains. They have been developed by rigorous testing of protease inhibition for yeast, E.coli, insect cells and mammalian cell lysates. They contain both irreversible and reversible protease inhibitors and are available with and without EDTA to purify histidine-tagged proteins by immobilized metal ion affinity chromatography (IMAC). cOmplete™ tablets are conveniently supplied in glass vials and EASYpack blister packs for apportioning of exact doses. Inhibit proteases effectively by simply dropping one cOmplete™ tablet in lysis buffer.

  • Increase fully intact protein yield: Quickly inhibit a broad range of proteases using this improved protease inhibitor cocktail.
  • Obtain cOmplete™ protection: This inhibitor cocktail is optimized for eukaryotic, yeast and bacterial cell lysates.
  • Ensure laboratory safety: Using cOmplete™ ULTRA Tablets allows you to avoid contact with hazardous compounds.

To ensure that full-length proteins are obtained, Roche developed cOmplete™ ULTRA Tablets for the inhibition of an extended variety of proteases. This new formulation shows high inhibition ratios due to its broadened range of inhibitors compared to standard cOmplete™ Tablets.

Figure 1: Inhibition ratios of protease activity in CHO cell lysates by different inhibitor cocktails.

Figure 2: Inhibition ratios of aspartic protease activity by different inhibitor cocktails.


Protease Inhibitor Cocktails: Serine Proteases Cysteine Proteases Metallo Proteases Aspartic Proteases
cOmplete ULTRA Tablets, with EDTAa        
cOmplete ULTRA Tablets, EDTA-free        
cOmplete Tablets, with EDTA        
cOmplete Tablets, EDTA-free        

Table 1: Roche Protease Inhibitors Selection Guide. Choose from our variety of Protease Inhibitor Cocktails, or select one or several matching single protease inhibitors. The blue color scale shows inhibition abilities.


Protease / protease mixture Enzyme concentration (mg/ml) Percent protease inhibition by cOmplete™ ULTRA at +15°C to +25°C for 60 mins
Pancreas Extract 0.027 94%
Trypsin 0.0036 95%
Papain 0.0030 96%
Proteinase K 0.0008 95%

Table 2: Inhibition of specific proteases by cOmplete™ ULTRA Tablets.

cOmplete™ Lysis Kit

The cOmplete™ ULTRA tablets make cell lysis easier and faster than traditional methods such as freeze-thaw cycles, sonicators and glass beads. At the same time cells are lysed, a multitude of proteases can be inhibited by simply adding the cOmplete™ Lysis Kit either for bacteria or mammalian cells.

For bacteria use the cOmplete™ Lysis-B (2x) Kit to efficiently and gently extract proteins in small volumes from bacteria (e.g., E. coli) and simultaneously inhibit proteases in the lysate.

Figure 3: Comparison of bacterial lysis reagents.

Protease Inhibitor Cocktail Tablets

PhosSTOP™ tablets from Roche preserve your protein's original phosphorylation state allowing you to inhibit a wide range of phosphatase types, including acid, alkaline, serine/threonine, tyrosine, and dual-specificity phosphatases. Inhibit phosphatases in a variety of sample materials, such as mammalian, insect, or plant cells, as well as formalin-fixed, paraffin-embedded (FFPE) tissue sections. Quickly and effectively inhibit protein dephosphorylation in your in vitro studies by simply dropping a PhosSTOP™ tablet into 10 ml buffer. For maximum protection, inhibit both proteases and phosphatases at the same time by combining a cOmplete™ ULTRA tablet with a PhosSTOP™ tablet in the same buffer.

Phosphatases Units (U/10 ml) % Inhibition
Calf alkaline phosphatase 140 U 98.4%
Potato acidic phosphatase 2 U 93.7%
Human acidic phosphatase 640 U 99.5%
Rabbit PP1 200 U 98.6%
Human PP2A 500 U 94.4%
Human PTP 500 U 96.7%

Table 3: Effectively inhibit a broad range of phosphatases with a single PhosSTOP™ tablet. After 15 minutes incubation (1 tablet per 10 ml), the inhibitory efficiency of PhosSTOP™ tablet was evaluated for alkaline (AP) and acid (SP) phosphatases, as well as for serine/threonine (PP1 and PP2A) and tyrosine protein phosphatases.

Figure 4: Inhibition ratios of protease activity in E.coli-Lysate by different inhibitor cocktails in combination with Roche inhibitor for phosphatases.