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UniProt functional annotation for P00491 | ||
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| UniProt code: P00491. |
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| Organism: | |
Homo sapiens (Human). |
| Taxonomy: | |
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo. |
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| Function: | |
Catalyzes the phosphorolytic breakdown of the N-glycosidic bond in the beta-(deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate (PubMed:9305964, PubMed:23438750). Preferentially acts on 6-oxopurine nucleosides including inosine and guanosine (PubMed:9305964). {ECO:0000269|PubMed:23438750, ECO:0000269|PubMed:9305964}. |
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| Catalytic activity: | |
Reaction=inosine + phosphate = alpha-D-ribose 1-phosphate + hypoxanthine; Xref=Rhea:RHEA:27646, ChEBI:CHEBI:17368, ChEBI:CHEBI:17596, ChEBI:CHEBI:43474, ChEBI:CHEBI:57720; EC=2.4.2.1; Evidence={ECO:0000269|PubMed:23438750, ECO:0000269|PubMed:9305964}; |
| Catalytic activity: | |
Reaction=guanosine + phosphate = alpha-D-ribose 1-phosphate + guanine; Xref=Rhea:RHEA:13233, ChEBI:CHEBI:16235, ChEBI:CHEBI:16750, ChEBI:CHEBI:43474, ChEBI:CHEBI:57720; EC=2.4.2.1; Evidence={ECO:0000269|PubMed:9305964}; |
| Catalytic activity: | |
Reaction=2'-deoxyguanosine + phosphate = 2-deoxy-alpha-D-ribose 1- phosphate + guanine; Xref=Rhea:RHEA:27738, ChEBI:CHEBI:16235, ChEBI:CHEBI:17172, ChEBI:CHEBI:43474, ChEBI:CHEBI:57259; EC=2.4.2.1; Evidence={ECO:0000250|UniProtKB:P23492}; |
| Catalytic activity: | |
Reaction=2'-deoxyinosine + phosphate = 2-deoxy-alpha-D-ribose 1- phosphate + hypoxanthine; Xref=Rhea:RHEA:27750, ChEBI:CHEBI:17368, ChEBI:CHEBI:28997, ChEBI:CHEBI:43474, ChEBI:CHEBI:57259; EC=2.4.2.1; Evidence={ECO:0000250|UniProtKB:P23492}; |
| Activity regulation: | |
Inhibited by 5'-deaza-1'-aza-2c-deoxy-1'-(9- methylene)-Immucilin-G (DADMe-ImmG). {ECO:0000269|PubMed:23438750}. |
| Biophysicochemical properties: | |
Kinetic parameters: KM=45 uM for inosine (at 30 degrees Celsius and pH 7) {ECO:0000269|PubMed:9305964}; KM=68 uM for inosine (at 25 degrees Celsius and pH 7.4) {ECO:0000269|PubMed:23438750}; KM=10 uM for hypoxanthine (at 30 degrees Celsius and pH 7) {ECO:0000269|PubMed:9305964}; KM=6 uM for guanosine (at 30 degrees Celsius and pH 7) {ECO:0000269|PubMed:9305964}; KM=12 uM for guanine (at 30 degrees Celsius and pH 7) {ECO:0000269|PubMed:9305964}; KM=650 uM for adenosine (at 30 degrees Celsius and pH 7) {ECO:0000269|PubMed:9305964}; KM=440 uM for adenine (at 30 degrees Celsius and pH 7) {ECO:0000269|PubMed:9305964}; Note=kcat is 57 sec(-1) with inosine as substrate (PubMed:9305964). kcat is 47 sec(-1) with inosine as substrate (PubMed:23438750). kcat is 70 sec(-1) with hypoxanthine as substrate (PubMed:9305964). kcat is 28 sec(-1) with guanosine as substrate (PubMed:9305964). kcat is 48 sec(-1) with guanine as substrate (PubMed:9305964). kcat is 0.0024 sec(-1) with adenosine as substrate (PubMed:9305964). kcat is 0.31 sec(-1) with adenine as substrate (PubMed:9305964). {ECO:0000269|PubMed:23438750, ECO:0000269|PubMed:9305964}; |
| Pathway: | |
Purine metabolism; purine nucleoside salvage. {ECO:0000269|PubMed:9305964}. |
| Subunit: | |
Homotrimer. {ECO:0000305|PubMed:23438750}. |
| Subcellular location: | |
Cytoplasm {ECO:0000269|PubMed:22509282}. |
| Tissue specificity: | |
Expressed in red blood cells; overexpressed in red blood cells (cytoplasm) of patients with hereditary non-spherocytic hemolytic anemia of unknown etiology. {ECO:0000269|PubMed:22509282}. |
| Disease: | |
Purine nucleoside phosphorylase deficiency (PNPD) [MIM:613179]: A disorder that interrupts both the catabolism of inosine into hypoxanthine and guanosine into guanine, and leads to the accumulation of guanosine, inosine, and their deoxified by-products. The main clinical presentation is recurrent infections due to severe T- cell immunodeficiency. Some patients also have neurologic impairment. {ECO:0000269|PubMed:1384322, ECO:0000269|PubMed:3029074, ECO:0000269|PubMed:8931706}. Note=The disease is caused by variants affecting the gene represented in this entry. |
| Similarity: | |
Belongs to the PNP/MTAP phosphorylase family. {ECO:0000305}. |
Annotations taken from UniProtKB at the EBI.