EC 3.1.3.64     
Accepted name: phosphatidylinositol-3-phosphatase
Reaction: 1-phosphatidyl-1D-myo-inositol 3-phosphate + H2O = 1-phosphatidyl-1D-myo-inositol + phosphate
Glossary: inositol 1-phosphate = Ins-1-P
inositol 1,3-bisphosphate = Ins(1,3)P2
1-phosphatidyl-1D-myo-inositol = PtdIns
1-phosphatidyl-1D-myo-inositol 3-phosphate = PtdIns3P
Other name(s): inositol-1,3-bisphosphate 3-phosphatase; inositol 1,3-bisphosphate phosphatase; inositol-polyphosphate 3-phosphatase; D-myo-inositol-1,3-bisphosphate 3-phosphohydrolase; phosphatidyl-3-phosphate 3-phosphohydrolase
Systematic name: 1-phosphatidyl-1D-myo-inositol-3-phosphate 3-phosphohydrolase
Comments: This enzyme still works when the 2,3-bis(acyloxy)propyl group is removed, i.e., it hydrolyses Ins(1,3)P2 to Ins-1-P.
References:
1.  Lips, D.L. and Majerus, P.W. The discovery of a 3-phosphomonoesterase that hydrolyzes phosphatidylinositol 3-phosphate in NIH 3T3 cells. J. Biol. Chem. 264 (1989) 19911–19915. [PMID: 2555336]
2.  Caldwell, K.K., Lips, D.L., Bansal, V.S. and Majerus, P.W. Isolation and characterization of two 3-phosphatases that hydrolyze both phosphatidylinositol 3-phosphate and inositol 1,3-bisphosphate. J. Biol. Chem. 266 (1991) 18378–18386. [PMID: 1655747]
[EC 3.1.3.64 created 1992, [EC 3.1.3.65 created 1992, incorporated 2002], modified 2002]]
 
 
EC 3.1.3.66     
Accepted name: phosphatidylinositol-3,4-bisphosphate 4-phosphatase
Reaction: 1-phosphatidyl-myo-inositol 3,4-bisphosphate + H2O = 1-phosphatidyl-1D-myo-inositol 3-phosphate + phosphate
Glossary: inositol 3-phosphate = Ins-3-P
inositol 1,3-bisphosphate = Ins(1,3)P2
inositol 3,4-bisphosphate = Ins(3,4)P2
inositol 1,3,4-trisphosphate = Ins(1,3,4)P3
1-phosphatidyl-1D-myo-inositol 3-phosphate = PtdIns3P
1-phosphatidyl-1D-myo-inositol 4-phosphate = PtdIns4P
Other name(s): inositol-3,4-bisphosphate 4-phosphatase; D-myo-inositol-3,4-bisphosphate 4-phosphohydrolase; phosphoinositide 4-phosphatase; inositol polyphosphate 4-phosphatase; inositol polyphosphate 4-phosphatase type II
Systematic name: 1-phosphatidyl-1D-myo-inositol-3,4-bisphosphate 4-phosphohydrolase
Comments: Mg2+-independent. This enzyme still works when the 2,3-bis(acyloxy)propyl group is removed, i.e., it hydrolyses Ins(1,3,4)P3 to Ins(1,3)P2. It also converts Ins(3,4)P2 into Ins-3-P.
References:
1.  Howell, S., Barnaby, R.J., Rowe, T., Ragan, C.I. and Gee, N.S. Evidence for at least four different inositol bisphosphatases in bovine brain. Eur. J. Biochem. 183 (1989) 169–172. [PMID: 2546770]
2.  Norris, F.A., Auethavekiat, V. and Majerus, P.W. The isolation and characterization of cDNA encoding human and rat brain inositol polyphosphate 4-phosphatase. J. Biol. Chem. 270 (1995) 16128–16133. [PMID: 7608176]
3.  Norris, F.A., Atkins, R.C. and Majerus, P.W. The cDNA cloning and characterization of inositol polyphosphate 4-phosphatase type II. Evidence for conserved alternative splicing in the 4-phosphatase family. J. Biol. Chem. 272 (1997) 23859–23864. [PMID: 9295334]
[EC 3.1.3.66 created 1992, modified 2002]