Inositol-trisphosphate 3-kinase

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In enzymology, an inositol-trisphosphate 3-kinase (EC is an enzyme that catalyzes the chemical reaction

ATP + 1D-myo-inositol 1,4,5-trisphosphate ADP + 1D-myo-inositol 1,3,4,5-tetrakisphosphate

Thus, the two substrates of this enzyme are ATP and 1D-myo-inositol 1,4,5-trisphosphate, whereas its two products are ADP and 1D-myo-inositol 1,3,4,5-tetrakisphosphate.

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:1D-myo-inositol-1,4,5-trisphosphate 3-phosphotransferase. Other names in common use include 1D-myo-inositol-trisphosphate 3-kinase, and Ins(1,4,5)P3 3-kinase. This enzyme participates in 3 metabolic pathways: inositol phosphate metabolism, calcium signaling pathway, and phosphatidylinositol signaling system. This enzyme has at least one effector, Calcium.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1TZD, 2A98, and 2AQX.


  • IUBMB entry for
  • BRENDA references for (Recommended.)
  • PubMed references for
  • PubMed Central references for
  • Google Scholar references for
  • Hansen CA, Mah S, Williamson JR (1986). "Formation and metabolism of inositol 1,3,4,5-tetrakisphosphate in liver". J. Biol. Chem. 261: 8100&ndash, 3. PMID 3487541.
  • Irvine RF, Letcher AJ, Heslop JP, Berridge MJ (1986). "The inositol tris/tetrakisphosphate pathway — demonstration of Ins(1,4,5)P3 3-kinase activity in animal tissues". Nature. 320: 631&ndash, 4. PMID 3010126.
  • Irvine RF, Schell MJ (2001). "Back in the water: the return of the inositol phosphates". Nat. Rev. Mol. Cell. Biol. 2: 327&ndash, 38. PMID 11331907.

External links

The CAS registry number for this enzyme class is 106283-10-7.

Gene Ontology (GO) codes