| Polynucleotide Phosphorylase | |
|---|---|
| Structure of the PNPase trimer | |
| Identifiers | |
| Symbol | PNPASE |
| Alt. symbols | PNPase, OLD35, old-35 |
| Entrez | 87178 |
| HUGO | 23166 |
| OMIM | 610316 |
| PDB | 1E3P |
| RefSeq | NM_033109 |
| UniProt | Q8TCS8 |
| Other data | |
| EC number | 2.7.7.8 |
| Locus | Chr. 2 p15 |
Polynucleotide Phosphorylase (PNPase) is a bifunctional enzyme with a phosphorolytic 3' to 5' exoribonuclease activity and a 3'-terminal oligonucleotide polymerase activity.[1] It is involved on mRNA processing and degradation in bacteria, plants,[2] and in humans.[3]
In humans, the enzyme is encoded by the PNPT1 gene. In its active form, the protein forms a ring structure consisting of three PNPase molecules. Each PNPase molecule consists of two RNase PH domains, an S1 RNA binding domain and an K-homology domain. The protein is present in bacteria and in the chloroplasts[1] and mitochondria[4] of some eukaryotic cells. In eukaryotes and archaea, a structurally and evolutionary related complex exists, called the exosome.[4]
The same abbreviation (PNPase) is also used for another, otherwise unrelated enzyme, Purine nucleoside phosphorylase.
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