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| rdf:type | |
| biopax3:cellularLocation | |
| biopax3:comment |
Two closely related but previously uncharacterized proteins similar to |FRAME: HS03602| were discovered by two labs independently. One lab named them DIPP3α and DIPP3β |CITS: [12105228]| while the other named them hAps2 and hAps1 |CITS: [12121577]|. The proteins, which are encoded by the |FRAME: HS04604| and |FRAME: HS05381| genes, respectively, differ from each other by a single amino acid. The genes reside on the X chromosome only 152 kbp apart |CITS: [12105228]|. Both proteins are cytoplasmic, and both metabolize diadenosine-polyphosphates and diphosphoinositol polyphosphates. Northern hybridizations revealed strong expression in the testis, medium expression in the brain, and very low expression in other tissues |CITS: [12105228]|. The |FRAME: HS05381| gene was cloned into an expression vector with a GST-tag and expressed in Escherichia coli , and the recombinant protein was purified |CITS: [12121577]|. Activity required |FRAME: MN+2|. Based on |CITS: [12121577]|, adenosine dinucleosides were by far the preferred substrates for this enzyme. |FRAME: CPD-11932| and |FRAME: CPD0-1137| were hydrolyzed to AMP and |FRAME: CPD-11561| and |FRAME: CPD-607|, respectively. |FRAME: CPD-11561| was further hydrolyzed to |FRAME: CPD-607| and then to ATP, making the final products ATP and AMP. Despite the sequence similarity to |FRAME: HS03602| and |FRAME: HS10696|, this study found that the enzyme had little activity towards diphosphoinositol phosphates. Surprisingly, the study by |CITS: [12105228]| found exactly the opposite, suggesting that diphosphoinositol phosphates are the preferred <i>in vivo</i> substrates for the enzyme. The enzyme also has |FRAME: PRPP| (PRPP) pyrophosphatase activity that generates the glycolytic activator ribose 1,5-bisphosphate |CITS: [12370170]|.
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| biopax3:dataSource | |
| biopax3:displayName |
diphosphoinositol polyphosphate phosphohydrolase 3β
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| biopax3:name |
diadenosine 5',5'''-P1,P6-hexaphosphate hydrolase 3-beta,
hDIPP3beta
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| biopax3:entityReference | |
| biopax3:standardName |
diphosphoinositol polyphosphate phosphohydrolase 3β
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