A p-nitrophenyl phosphorylcholine phosphodiesterase from mouse brain.

The phosphodiesterase which catalyzes the hydrolysis of p-nitrophenyl phosphorylcholine was solubilized from mouse brain by 1% sodium deoxycholate treatment, and partially purified by HPLC gel chromatography. The enzyme, tightly bound to membranes and relatively stable, possessed apparent values of Km of 1 mM and Vmax of 150 n moles/mg. hr, and gave optimum pH of 11. Additionally, the molecular weight of the enzyme, EDTA-insensitive and divalent ions-independent, was estimated to be 150,000. Based on these results, this phosphodiesterase is supposed to be different from the phosphodiesterases reported previously.