PP1C, Protein Phosphatase 1
Source: Rabbit skeletal muscle
Purity: > 90% by SDS-PAGE, apparent Mr ~ 36-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: ~ 2000 units/mg with 32P-labeled phosphorylase as substrate. One unit is the amount of PP1C that releases 1 nmol of inorganic phosphate from 32P-labeled phosphorylase per min. Maintain preparations in aliquots at -70° C. Avoid repeated thawing.
Synonyms: Catalytic Subunit of Protein Phosphatase 1; Protein Phosphatase 1C; PP1C
Figure: SDS-PAGE of a sample of a purified preparation of PP1C. The gel was stained with Coomassie Blue.
In contrast to widely available recombinant forms of the enzyme, PP1C isolated from rabbit skeletal muscle and other tissue sources is divalent cation-independent. Its activity is nonetheless stimulated by Mn2+ with several substrates.
Background: Protein phosphatase 1 (PP1) is one of the four major cytoplasmic protein serine/threonine phosphatases present in all mammalian cells. It is highly conserved and has been found to play a key role in the cell cycle and cell proliferation activities. The enzyme is a growth factor-stimulated divalent cation independent phosphatase. It is inhibited by a number of toxins including mycrocyctins, calyculins (clavosine A and B), nodularins, and okadaic acid. The enzyme is phosphorylated on its catalytic subunit at Thr320 by cdc2 kinase, resulting in inhibition of the phosphatase.
References: Biochem J 287: 1019; Proc Natl Acad Sci USA 90: 2500
