CATH Classification

Domain Context

CATH Clusters

Superfamily 3.30.1490.220
Functional Family Inositol-tetrakisphosphate 1-kinase

Enzyme Information

2.7.1.134
Inositol-tetrakisphosphate 1-kinase.
based on mapping to UniProt Q9XYQ1
ATP + 1D-myo-inositol 3,4,5,6-tetrakisphosphate = ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate.
-!- This enzyme also phosphorylates Ins(1,3,4)P(3) on O-5 and O-6. -!- The phosphotransfer from ATP to either inositol 1,3,4-trisphosphate or inositol 3,4,5,6-tetrakisphosphate appears to be freely reversible to the extent that the enzyme can act like an inositol polyphosphate phosphatase in the presence of ADP. -!- It can also catalyze an isomerization between Ins(1,3,4,5)P(4) and Ins(1,3,4,6)P(4) in the presence of ADP. -!- Formerly EC 2.7.1.133 and EC 2.7.1.139.
2.7.1.159
Inositol-1,3,4-trisphosphate 5/6-kinase.
based on mapping to UniProt Q9XYQ1
(1) ATP + 1D-myo-inositol 1,3,4-trisphosphate = ADP + 1D-myo-inositol 1,3,4,5-tetrakisphosphate. (2) ATP + 1D-myo-inositol 1,3,4-trisphosphate = ADP + 1D-myo-inositol 1,3,4,6-tetrakisphosphate.
-!- In humans, this enzyme, along with EC 2.7.1.127, EC 2.7.1.140 and EC 2.7.1.158 is involved in the production of inositol hexakisphosphate (InsP(6)). -!- InsP(6) is involved in many cellular processes, including mRNA export from the nucleus. -!- Yeast do not have this enzyme, so produce InsP(6) from Ins(1,4,5)P(3) by the actions of EC 2.7.1.151 and EC 2.7.1.158.

UniProtKB Entries (1)

Q9XYQ1
ITPK1_ENTHI
Entamoeba histolytica
Inositol-tetrakisphosphate 1-kinase

PDB Structure

PDB 1Z2O
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Specificity determinants in inositol polyphosphate synthesis: crystal structure of inositol 1,3,4-trisphosphate 5/6-kinase.
Miller, G.J., Wilson, M.P., Majerus, P.W., Hurley, J.H.
Mol.Cell