PP2B, Protein Phosphatase 2B
Source: Bovine brain.
Purity: > 90% by SDS-PAGE, subunit apparent Mr’s ~ 60- and 15-kDa.
Supplied: 1 μg in 50 μl 50 mM Tris-HCl pH 7.0 buffer containing 14 mM β-mercaptoethanol, 1 mM benzamidine, 0.1 mM phenylmethanesulfonyl fluoride, 1 mM EDTA and 50% glycerol.
Activity: ~ 600 units/mg with 32P-labeled Myelin Basic Protein (MBP) as substrate. One unit is the amount of PP2B that releases 1 nmol of inorganic phosphate from 32P-labeled MBP per min. Maintain all preparations at -70° C. Avoid repeated thawing.
Synonyms: Protein Phosphatase 2B; Calcineurin; PP2B
Background: Protein Phosphatase 2B (PP2B) is one of the four major cytoplasmic protein serine threonine phosphatases present in mammalian cells. It is calcium calmodulin-dependent and involved in regulating numerous cellular processes. PP2B is the major calmodulin-binding protein in brain and inhibits the calmodulin activation of phosphodiesterase 3′:5′ cyclic nucleotide. It has similar effects on adenylate cyclase. PP2B regulates T-cell activation as evidenced by its inhibition in cells with the immunosuppressive drugs FK-506 and cyclosporin A. The enzyme is also involved in the hyperphosphorylation of tau protein in Alzheimer’s disease. It also prevents calpain-mediated proteolysis of tau in differentiated PC12 cells, and regulates secretory functions in a variety of cells.
GloboZymes native PP2B preparations are useful for the study of enzyme kinetics and regulation, to dephosphorylate target substrates, and to evaluate the effects of test substances on the activity of the phosphatase.
Reference: Biochem J 287: 1019