Hypoxanthine-guanine phosphoribosyltransferase
Short name=HGPRT
Short name=HGPRTase
EC=2.4.2.8
- Converts guanine to guanosine monophosphate, and hypoxanthine to inosine monophosphate. Transfers the 5-phosphoribosyl group from 5-phosphoribosylpyrophosphate onto the purine. Plays a central role in the generation of purine nucleotides through the purine salvage pathway.
- Binds 2 magnesium ions per subunit. The magnesium ions are essentially bound to the substrate and have few direct interactions with the protein.
- Lesch-Nyhan syndrome (LNS) [MIM:300322]: Characterized by complete lack of enzymatic activity that results in hyperuricemia, choreoathetosis, mental retardation, and compulsive self-mutilation.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.19 Ref.23 Ref.24 Ref.30 Ref.33 Ref.34 Ref.35 Ref.37 Ref.43 Ref.45
Gout HPRT-related (GOUT-HPRT) [MIM:300323]: Characterized by partial enzyme activity and hyperuricemia.
Note: The disease is caused by mutations affecting the gene represented in this entry.
Adenine phosphoribosyltransferase
Short name=APRT
EC=2.4.2.7
- Function
- Catalyzes a salvage reaction resulting in the formation of AMP, that is energically less costly than de novo synthesis. HAMAP-Rule MF_00004
- Catalytic activity
- AMP + diphosphate = adenine + 5-phospho-alpha-D-ribose 1-diphosphate. HAMAP-Rule MF_00004
- Pathway
- Purine metabolism; AMP biosynthesis via salvage pathway; AMP from adenine: step 1/1. HAMAP-Rule MF_00004
- Subunit structure
- Homodimer.
- Subcellular location
- Cytoplasm HAMAP-Rule MF_00004.
- Involvement in disease
- Adenine phosphoribosyltransferase deficiency (APRTD) [MIM:614723]: An enzymatic deficiency that can lead to urolithiasis and renal failure. Patients have 2,8-dihydroxyadenine (DHA) urinary stones.
- Note: The disease is caused by mutations affecting the gene represented in this entry.
