Purine nucleosidase

In enzymology, a purine nucleosidase (EC 3.2.2.1) is an enzyme that catalyzes the chemical reaction

a purine nucleoside + H₂O ${\displaystyle \rightleftharpoons }$ D-ribose + a purine base

purine nucleosidase
Purine nucleosidase tetramer, Saccharolobus solfataricus
Identifiers
EC no.	3.2.2.1
CAS no.	9025-44-9
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

Thus, the two substrates of this enzyme are purine nucleoside and H₂O, whereas its two products are D-ribose and purine base.

This enzyme belongs to the family of hydrolases, specifically those glycosylases that hydrolyse N-glycosyl compounds. The systematic name of this enzyme class is purine-nucleoside ribohydrolase. Other names in common use include nucleosidase, purine beta-ribosidase, purine nucleoside hydrolase, purine ribonucleosidase, ribonucleoside hydrolase, nucleoside hydrolase, N-ribosyl purine ribohydrolase, nucleosidase g, N-D-ribosylpurine ribohydrolase, inosine-adenosine-guanosine preferring nucleoside hydrolase, purine-specific nucleoside N-ribohydrolase, IAG-nucleoside hydrolase, and IAG-NH. This enzyme participates in purine metabolism and nicotinate and nicotinamide metabolism.

Structural studies

As of late 2007, 11 structures have been solved for this class of enzymes, with PDB accession codes 1EZR, 1HOZ, 1HP0, 1KIC, 1KIE, 1MAS, 1R4F, 2C40, 2FF1, 2FF2, and 2MAS.