ectonucleoside triphosphate diphosphohydrolase 4; NTPDase 4; lysosomal apyrase-like protein of 70 kD; uridine-diphosphatase; UDPase (ENTPD4 KIAA0392 LALP70 LYSAL1)

Function

• hydrolyzes preferentially nucleoside 5'-diphosphates,
• nucleoside 5'-triphosphates are hydrolyzed only to a minor extent
• the order of activity with different substrates is: UDP >> GDP = CDP = TDP
• AMP, ADP, ATP & UMP are not substrates
• preferred substrates for isoform 2 are CTP, UDP, CDP, GTP & GDP
• isoform 1 utilizes UTP & TTP

Cofactor:

• Ca+2, Mg+2
• isoform 1 requires Ca+2 & to a lesser extent, Mg+2
• isoform 2 is equally dependent on Ca+2 & Mg+2

Structure

belongs to the GDA1/CD39 NTPase family

Compartment

• multi-pass membrane protein
• Golgi membrane (putative)
• cytoplasmic vesicle, autophagosome membrane
• localizes in the Golgi & autophagic vacuoles/lysosomes

Alternative splicing

named isoforms=2

Expression

• ubiquitous
• highest expression in testis
• lowest expression in bladder

More general terms

• ectonucleoside triphosphate diphosphohydrolase
• transmembrane 2 protein

Additional terms

• CD39 like protein (CD39 like antigen, CD39L, ectonucleoside triphosphate diphosphohydrolase)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=9583
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:9583
• OMIM: https://mirror.omim.org/entry/607577
• UniProt: http://www.uniprot.org/uniprot/Q9Y227.html