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Catalytic Site Atlas

CSA LITERATURE entry for 1inp

E.C. nameinositol-1,4-bisphosphate 1-phosphatase
SpeciesBos taurus (Bovine)
E.C. Number (IntEnz) 3.1.3.57
CSA Homologues of 1inpThere are 10 Homologs
CSA Entries With UniProtID P21327
CSA Entries With EC Number 3.1.3.57
PDBe Entry 1inp
PDBSum Entry 1inp
MACiE Entry 1inp

Literature Report

IntroductionInositol polyphosphate 1 -phosphatase (l-ptase) removes the l-position phosphate from inositol 1,4-bisphosphate, yielding inositol 4-phosphate. l-Ptase is a ubiquitous monomeric enzyme that requires Mg2+ for activity and is potently inhibited by Li+, leading to its use in therapeutic targets of lithium treatment for manic-depressive illnesses.
MechansimAs with most phosphatases the mechanism involves nucleophilic attack on the phosphate group. The nucleophile is an activated water molecule, which is co-ordinated to two magnesium cofactors and then activated by Thr158. This attacks the phosphate group forming a trigonal bipyramidal transition state which is stabilised by the magnesium ions, break down of this leads to the the inositol 4-phosphate.
Note there have been proposals for 2 and 3 magnesium ions models. This PDB code relates to a two magnesium-site enzyme.
Reaction

Catalytic Sites for 1inp

Literature References

Notes:
York JD
Crystal structure of inositol polyphosphate 1-phosphatase at 2.3-A resolution.
Biochemistry 1994 33 13164-13171
PubMed: 7947723
Patel S
Crystal structure of an enzyme displaying both inositol-polyphosphate-1-phosphatase and 3'-phosphoadenosine-5'-phosphate phosphatase activities: a novel target of lithium therapy.
J Mol Biol 2002 315 677-685
PubMed: 11812139
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