diphosphoinositol polyphosphate phosphohydrolase 3 alpha (DIPP-3 alpha, DIPP3 alpha, hDIPP3alpha,diadenosine 5',5'-P1,P6-hexaphosphate hydrolase 3 alpha, nucleoside diphosphate-linked moiety X motif 10, Nudix motif 10, hAps2, NUDT10, APS2, DIPP3A)
Jump to navigation
Jump to search
Function
- cleaves a beta-phosphate from diphosphate groups in PP-InsP5 (diphosphoinositol pentakisphosphate)
- role in signal transduction
- catalyzes hydrolysis of dinucleoside oligophosphates, with Ap6A & Ap5A as preferred substrates.
- major reaction products are ADP and p4a from Ap6A & ADP & ATP from Ap5A
- able to hydrolyze PRPP (5-phosphoribosyl 1-pyrophosphate)
diphospho-myo-inositol polyphosphate + H2O
<-->
myo-inositol polyphosphate + phosphate
Cofactor:
- Mg+2 or Mn+2
- Mn+2 cofactor in vivo
Kinetic parameters:
- KM=0.088 uM for PP-InsP5
- KM=19 uM for Ap6A
- KM=50 uM for Ap5A
- Optimum pH is 8.5
Structure
belongs to the Nudix hydrolase family. DIPP subfamily
Compartment
Expression
- mainly expressed in testis
- expressed at a lower level in brain