ENTPD4

This gene encodes a member of the apyrase protein family. Apyrases are enzymes that catalyze the hydrolysis of nucleotide diphosphates and triphosphates in a calcium or magnesium-dependent manner. The encoded protein is an endo-apyrase and may play a role in salvaging nucleotides from lysosomes.

ectonucleoside triphosphate diphosphohydrolase 4

Isoform 1:
Catalyzes the hydrolysis of nucleoside triphosphates and diphosphates in a calcium- or magnesium-dependent manner, with a preference for pyrimidines. Preferentially hydrolyzes UTP and TTP. AMP, ADP, ATP and UMP are not substrates (PubMed:10858452, PubMed:9556635).

Preferentially activated by Ca2+ over Mg2+ (PubMed:10858452).

Isoform 2:
Has a broad substrate specificity with the ability of cleaving all nucleotide di- and triphosphates with the exception of adenosine di- and triphosphate (ADP and ATP). Preferentially hydrolyzes CTP, UDP, CDP, GTP and GDP. Can use either Ca2+ or Mg2+ equally.

CTP metabolic process Source: UniProtKB
GDP catabolic process Source: UniProtKB
Nucleobase-containing small molecule catabolic process Source: UniProtKB
Nucleoside diphosphate catabolic process Source: GO_Central
UDP catabolic process Source: UniProtKB

Isoform 1: Lysosome membrane; Autophagosome membrane
Isoform 2: Golgi apparatus membrane

Cytoplasmic: 1-33
Helical: 34-54
Lumenal: 55-559
Helical: 560-580
Cytoplasmic: 581-616