nucleotide-binding domain (NBD) of the ectonucleoside triphosphate diphosphohydrolase 4 (NTPDase4)-like subfamily
The NTPDase4-like subfamily includes NTPDase4 and NTPDase7. NTPDase4 (EC 3.6.1.15/EC 3.6.1.6/EC 3.6.1.42), also called Golgi UDPase, lysosomal apyrase-like protein of 70 kDa (LALP70), uridine-diphosphatase (UDPase), is located in the Golgi. It catalyzes the hydrolysis of nucleoside triphosphates and diphosphates in a calcium- or magnesium-dependent manner, with a preference for pyrimidines. It preferentially hydrolyzes UTP and TTP. NTPDase4 has at least one alternatively spliced variant, which has a broad substrate specificity with the ability of cleaving all nucleotide di- and triphosphates except for adenosine di- and triphosphate (ADP and ATP). It preferentially hydrolyzes CTP, UDP, CDP, GTP and GDP, and can use either calcium or magnesium equally. NTPDase7 (EC 3.6.1.15), also called lysosomal apyrase-like protein 1 (LALP1), is a novel mammalian endo-apyrase with substrate preference for nucleoside 5'-triphosphates UTP, GTP, and CTP.