IUBMB Enzyme Nomenclature


Accepted name: phosphoinositide 5-phosphatase

Reaction: 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + H2O = 1-phosphatidyl-1D-myo-inositol 4-phosphate + phosphate

For diagram click here.

Glossary: 1-phosphatidyl-1D-myo-inositol 4-phosphate = PtdIns4P
1-phosphatidyl-1D-myo-inositol 1,4-bisphosphate = PtdIns(1,4)P2
1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate = PtdIns(4,5)P2
1-phosphatidyl-1D-myo-inositol 1,3,4-trisphosphate = PtdIns(1,3,4)P3
1-phosphatidyl-1D-myo-inositol 1,4,5-trisphosphate = PtdIns(1,4,5)P3
1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate = PtdIns(3,4,5)P3
1-phosphatidyl-1D-myo-inositol 1,3,4,5-tetrakisphosphate = PtdIns(1,3,4,5)P4

Other name(s): type II inositol polyphosphate 5-phosphatase; triphosphoinositide phosphatase; IP3 phosphatase; PtdIns(4,5)P2 phosphatase; triphosphoinositide phosphomonoesterase; diphosphoinositide phosphatase; inositol 1,4,5-triphosphate 5-phosphomonoesterase; inositol triphosphate 5-phosphomonoesterase; phosphatidylinositol-bisphosphatase; phosphatidyl-myo-inositol-4,5-bisphosphate phosphatase; phosphatidylinositol 4,5-bisphosphate phosphatase; polyphosphoinositol lipid 5-phosphatase; phosphatidyl-inositol-bisphosphate phosphatase

Systematic name: phosphatidyl-myo-inositol-4,5-bisphosphate 4-phosphohydrolase

Comments: These enzymes can also remove the 5-phosphate from Ins(1,4,5)P3 and/or Ins(1,3,4,5)P4. They are a diverse family of enzymes, with differing abilities to catalyse two or more of the four reactions listed. They are thought to use inositol lipids rather than inositol phosphates as substrates in vivo. All of them can use either or both of PtdIns(4,5)P2 and PtdIns(3,4,5)P3 as substrates; this is the main property that distinguishes them from EC, inositol-polyphosphate 5-phosphatase.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9036-01-5


1. Dawson, R.M.C. and Thompson, W. The triphosphoinositide phosphomonoesterase of brain tissue. Biochem. J. 91 (1964) 244-250. [PMID: 4284485]

2. Roach, P.D. and Palmer, F.B.S. Human erythrocyte cytosol phosphatidyl-inositol-bisphosphate phosphatase. Biochim. Biophys. Acta 661 (1981) 323-333. [PMID: 6271223]

3. Woscholski, R. and Parker, P.J. Inositol phosphatases: constructive destruction of phosphoinositides and inositol phosphates. In: Cockcroft, S. (Ed.), Biology of Phosphoinositides, Oxford University Press, Oxford, 2000, pp. 320-338.

[EC created 1972, modified 2002]

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