ENTPD4 (Ectonucleoside triphosphate diphosphohydrolase 4) preferentially hydrolyzes 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 and UMP are not substrates. There are two named isoforms. The preferred substrates for isoform 2 are CTP, UDP, CDP, GTP and GDP, while isoform 1 utilizes UTP and TTP.
Golgi apparatus membrane; Multi-pass membrane protein. Cytoplasmic vesicle, autophagosome membrane; Multi-pass membrane protein. Note: Localizes in the Golgi and autophagic vacuoles/lysosomes.