Catalyzes the hydrolysis of phosphorylcholine (PCho) to produce choline and inorganic phosphate (PubMed:2116592, PubMed:10387109, PubMed:15886911, PubMed:17106798). Can also hydrolyze phosphorylethanolamine and the nonphysiological substrate p-nitrophenylphosphate (pNPP) (PubMed:2116592, PubMed:10387109, PubMed:15886911, PubMed:17106798). Shows higher affinity and catalytic efficiency with phosphorylcholine as substrate (PubMed:2116592). Is probably involved in virulence (PubMed:19103776, Ref.3). The bacteria may break down various host compounds or host cell membranes through the coordinated action of phospholipase C and phosphocholine phosphatase. The final consequence of the action of these enzymes is an increase of the free choline concentration, which may promote the pathogenicity of P.aeruginosa (Ref.3). H2O + phosphocholine = choline + phosphate H2O + phosphoethanolamine = ethanolamine + phosphate At pH 5.0 Mg(2+), Zn(2+) or Cu(2+) is required for maximal activity (PubMed:10387109, PubMed:18801468). Mg2(+) shows low affinity with respect to Zn(2+) as a cofactor, but it is probably the preferred cation due to its abundance and its ability to work in a broad range of pH conditions (PubMed:20135339). Activity is inhibited by high concentrations of phosphorylcholine, phosphorylethanolamine, choline or betaine (PubMed:2116592, PubMed:15886911, PubMed:21515416). Displays different properties depending on the substrate utilized, the pH conditions as well as the presence or absence of metal ions (PubMed:10387109, PubMed:21660097). At pH 5, activity is inhibited by Al(3+) ions. At pH 7.4, the enzyme cannot catalyze the hydrolysis of pNPP, phosphorylethanolamine is a poor substrate in either the presence or absence of divalent cations, and activity measured with phosphorylcholine is independent of divalent cations or is not inhibited by Al(3+) ions (PubMed:10387109). Mg(2+) produces identical activation at pH 5.0 and 7.4, but Zn(2+) is an activator at pH 5.0 and becomes an inhibitor at pH 7.4 (PubMed:20135339). This inhibition at pH 7.4 may be due to a transition from octahedral to tetrahedral coordination geometry, which is produced by hydrolysis of the Zn-hexacoordinated complex (PubMed:20135339). Optimum pH is dependent on the substrate: optimum pH is 5-8 with phosphorylcholine, 6 with phosphorylethanolamine and 5 with pNPP. Monomer (PubMed:10387109, PubMed:15886911). Homodimer (PubMed:20064618, PubMed:20693680, PubMed:22922065). Homotetramer (PubMed:20693680). Induced in the presence of choline, betaine, glycine betaine or dimethylglycine (PubMed:2116592, PubMed:19103776, PubMed:20869215). Induction is mediated by the transcriptional regulator GbdR (PubMed:19103776, PubMed:20869215). The nitrogen regulatory protein NtrC is necessary for full pchP expression (PubMed:20869215). Expression is also partially dependent on the sigma-54 factor (PubMed:20869215). Induced via GbdR in bovine lung surfactant and mouse BALF (PubMed:19103776). Folds into three structural domains: the first domain harbors all the residues involved in catalysis, the second domain is characteristic of PchP and is involved in the recognition of the choline moiety of the substrate, the third domain stabilizes the relative position of the other two (PubMed:22922065). Contains two sites for alkylammonium compounds: one catalytic site near the metal ion-phosphoester pocket and one inhibitory site (PubMed:21515416, PubMed:21660097, PubMed:22922065). Sites are adjacent and share residues (PubMed:21515416). Contains a high and a low affinity site for phosphorylcholine (PubMed:10387109, PubMed:15886911). The signal peptide is the fundamental factor responsible for decreasing the affinity of the second site, and catalytic efficiency increases notably after cleavage of the signal peptide (PubMed:17106798). Belongs to the HAD-like hydrolase superfamily.