Description:
Protein phosphatase inhibitor-2 specifically inhibits the catalytic subunit of type 1 protein phosphatases (PP1) at nanomolar concentrations (IC₅₀ ~ 2 nM). Protein phosphatase inhibitor-2 can be used to distinguish type 1 protein phosphatases from type 2 protein phosphatases, which are the major protein serine/threonine phosphatases in eurkaryotic cells (1, 2). Human recombinant protein phosphatase inhibitor-2 is produced from E. coli., purified from freshly extracted E. coli lysates, and purified to homogeneity using methods developed by LAE Biotechnology Co., LTD. The final fraction of protein phosphatase inhibitor-2 exhibits a single polypeptide band of 31 kDa, which is a heat stable protein containing 204 amino acid residues.

Quality of Protein Phosphatase Inhibitor-2:

Molecular Weight:
Theoretical: 22,800 daltons and Apparent: 31,000 daltons

1X PP1 Reaction Buffer:
50 mM Tris-HCl, 5 mM dithiothreitol, 0.1 mM EDTA, pH 7.0

Reaction Conditions:
1X PP1 Reaction Buffer supplemented with 1 mM MnCl₂ and 5 mM Caffeine
Reaction should be performed at 30 C

Supply:
Protein phosphatase inhibitor-2 is supplied in lyophilized form at the dose of 100 ug per vail (Catalog # P027)

Reconstitution:
Lyophilized protein phosphatase inhibitor-2 should be should be reconstituted in 100 ul of 50 mM Tris-HCl, pH 7.0 to make a final concentration of 1 mg/ml.

Shipping/Storage:
protein phosphatase inhibitor-2 is shipped on ice and must be stored at -20 C or lower.

Legal consideration: FOR RESEARCH USE ONLY

Notes:
1. Supplement with 1 mM MnCl₂ and 5 mM caffeine (required only if phosphorylase a is the substrate).

2. Protein phosphatase inhibitor-2 has been purified to > 95% homogeneity as determined by SDS-PAGE and Coomassie Blue staining.

3. Recommended long term storage -70 C; avoid repeated freeze/thaw cycles.

Quality Assurance Statement:
Protein phosphatase inhibitor-2 contains no detectable protease activity. Tests for phosphatase activity showed no detectable activity.

References:
1. Ingebritsen, T.S. and Cohen, P. (1983) Eur. J. Biochem., 132, 255-261.

2. Cohen, P. (1991) Methods Enzymol., 201, 389-398.