hypoxanthine-guanine phosphoribosyltransferase (HGPRT, HPRT, HPRT1)

Function

• purine metabolism; IMP biosynthesis via salvage pathway
• IMP from hypoxanthine: step 1/1

IMP + diphosphate  <-->
hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate

GMP + diphosphate
   <-->
guanine + 5-phospho-alpha-D-ribose 1-diphosphate

Cofactor:

• binds 2 Mg+2 per subunit
• One of the ions does not make direct protein contacts

Structure

• homotetramer
• belongs to the purine/pyrimidine phosphoribosyltransferase family

Compartment

cytoplasm

Pathology

• defects in HPRT1 are the cause
  • Lesch-Nyhan syndrome
  • gout

Laboratory

• hypoxanthine phosphoribosyltransferase in amniotic fluid
• hypoxanthine phosphoribosyltransferase in chorionic villus
• hypoxanthine phosphoribosyltransferase in placenta
• hypoxanthine phosphoribosyltransferase in tissue
• hypoxanthine phosphoribosyltransferase in erythrocytes

More general terms

• phosphoribosyltransferase

Database

• UniProt: http://www.uniprot.org/uniprot/P00492.html
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3251
• OMIM: https://mirror.omim.org/entry/300322
• OMIM: https://mirror.omim.org/entry/300323
• OMIM: https://mirror.omim.org/entry/308000