Conserved Site

Inosine/uridine-preferring nucleoside hydrolase, conserved site (IPR015910)

Short name: I/U_nuclsd_hydro_CS


Inosine-uridine preferring nucleoside hydrolase (EC: (IU-nucleoside hydrolase or IUNH) is an enzyme first identified in protozoan [PMID: 8634237] that catalyzes the hydrolysis of all of the commonly occurring purine and pyrimidine nucleosides into ribose and the associated base, but has a preference for inosine and uridine as substrates. This enzyme is important for these parasitic organisms, which are deficient in de novo synthesis of purines, to salvage the host purine nucleosides. IUNH from Crithidia fasciculata has been sequenced and characterised, it is an homotetrameric enzyme of subunits of 34 Kd. An histidine has been shown to be important for the catalytic mechanism, it acts as a proton donor to activate the hypoxanthine leaving group.

IUNH is evolutionary related to a number of uncharacterised proteins from various biological sources.

This entry represents the highly conserved region located in the N-terminal extremity that contains the four conserved aspartates that have been shown to be located in the active site cavity [PMID: 8634238].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0016799 hydrolase activity, hydrolyzing N-glycosyl compounds

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns