Application

The phosphatase inhibitor cocktail improves the yields of intact proteins by adding inhibitors to enzymes that modify proteins present in cell extracts. This product has been tested on extract from animal tissues including human placenta and bovine liver, and on extracts of A431, CHO, and U937 cells. It has been optimized and tested for L-isozymes of alkaline phosphatase as measured with pNPP and for serine-threonine protein phosphatases.

Biochem/physiol Actions

This mixture contains individual components with specific inhibitory properties. Cantharidin inhibits protein phosphatase 2A. (-)-p-Bromolevamisole oxalate inhibits L-isoforms of alkaline phosphatases. Calyculin A inhibits protein phosphatases 1 and 2A.

Caution

As supplied, this product is stable for four years at the recommended 2-8°C storage temperature.

Preparation Note

This cocktail is supplied as a clear solution in dimethyl sulfoxide. It is recommended to dilute the cocktail at 1 mL of cocktail per 500 mg of protein extracted from tissue or cells. Often a final concentration of 1% (v/v) is used, which will inhibit phosphatase activities found in the 27,000 x g supernatant from human placenta and bovine liver, and in the 100,000 x g supernatant from A431, CHO, and U937 extracts.