Description:
DARPP-32 stands for dopamine- and cAMP-regulated protein with molecular weight of 32 kDa (1). DARPP-32 is an important component of dopaminergic function in the brain. It acts as an intracellular third messenger. DARPP-32 can be phosphorylated at Thr³⁴ by cAMP-dependent protein kinase. Phosphorylation of DARPP-32 results in its conversion to a potent inhibitor (IC50 approximately 1 nM) of the catalytic subunit of protein phosphatase-1 (PP1). Recombinant rat DARPP-32 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 rat DARPP-32 exhibits a single polypeptide band of 32 kDa. Phospho-DARPP-32 was prepared by phosphorylation at Thr³⁴ of DARPP-32 by cAMP-dependent protein kinase.

Quality of Rat Phospho-DARPP-32:

Supply:
Recombinant rat phospho-DARPP-32 is supplied in lyophilized form at the dose of 100 ug per vail (Catalog # P022) and at the dose of 50 ug per vail (Catalog # P023)

Reconstitution:
Lyophilized recombinant rat DARPP-32 (catalog # P022, 100 ug/vail) should be reconstituted in 100 ul of 50 mM Tris-HCl, pH 7.0, while lyophilized protein phosphatase inhibitor-1 (catalog # P023, 50 ug/vail) should be reconstituted in 50 ul of 50 mM Tris-HCl, pH 7.0, to make a final concentration of 1 mg/ml.

Shipping/Storage:
The recombinant rat DARPP-32 is shipped on ice and must be stored at -20 C or lower.

Legal consideration: FOR RESEARCH USE ONLY

Notes:
Recommended long term storage at -70 C; avoid repeated freeze/thaw cycles.

Quality Assurance Statement:
Recombinant rat phospho-DARPP-32 contains no detectable protease activity. Tests for phosphatase activity showed no detectable activity.

References:
1. Huang, H.-B., Horiuchi, A., Watanabe, T., Shih, S. R., Tsay, H. J., Li, H. C., Greengard, P., Nairn, A. C. (1999) Characterization of the inhibition of protein phosphastase-1 by DARPP-32 and inhibitor-2. J. Biol. Chem. 274, 7870-7878.