IUBMB Enzyme Nomenclature


Accepted name: inositol-1,4-bisphosphate 1-phosphatase

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

For diagram click here.

Other name(s): inositol-polyphosphate 1-phosphatase

Systematic name: 1D-myo-inositol-1,4-bisphosphate 1-phosphohydrolase

Comments: The enzyme acts on inositol 1,4-bisphosphate and inositol 1,3,4-trisphosphate (forming inositol 3,4-bisphosphate) with similar Vmax values for both substrates, but with a five-times higher affinity for the bisphosphate. Does not act on inositol 1-phosphate, inositol 1,4,5-trisphosphate or inositol 1,3,4,5-tetrakisphosphate.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 111070-17-8, 111694-13-4


1. Berridge, M.J., Dawson, R.M.C., Downes, C.P., Heslop, J.P. and Irvine, R.F. Changes in the levels of inositol phosphates after agonist-dependent hydrolysis of membrane phosphoinositides. Biochem. J. 212 (1983) 473-482. [PMID: 6309146]

2. Connolly, T.M., Bansal, V.S., Bross, T.E., Irvine, R.F. and Majerus, P.W. The metabolism of tris- and tetraphosphates of inositol by 5-phosphomonoesterase and 3-kinase enzymes. J. Biol. Chem. 262 (1987) 2146-2149. [PMID: 3029066]

3. Inhorn, R.C. and Majerus, P.W. Inositol polyphosphate 1-phosphatase from calf brain. Purification and inhibition by Li+, Ca2+, and Mn2+. J. Biol. Chem. 262 (1987) 15946-15952. [PMID: 2824473]

[EC created 1989, modified 2002]

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