CD39L4/ENTPD5: ProductsCD39L4 (also ER-UDPase, PCPH and Ectonucleoside triphosphate diphosphohydrolase 5/eNTPDase5) is a secreted, 45-51 kDa class II member of the GDA1/CD39 NTPase family of molecules. It is expressed by multiple cell types, including neurons, cardiomyocytes, and hepatocytes. CD39L4 is a divalent cation-dependent enzyme that preferentially hydrolyzes GDP and UDP. In the ER, this enzyme may remove UDP which interferes with proper protein folding and maturation. Extracellularly, CD39L4 may reduce available UDP ligand for P2Y receptors. Mature human CD39L4 is a 408 amino acid (aa) glycoprotein (aa 21-428). It contains four APR (apyrase conserved regions) (aa 54-206) that participate in NTPase activity. CD39L4 has been reported to exist as both monomer and homodimer. Three potential splice variants are reported. One shows a seven aa substitution for aa 401-428, a second contains a five aa substitution for aa 401-428, and a third possesses a 22 aa substitution for aa 215-428. Over aa 21-428, human CD39L4 shares 89% aa identity with mouse CD39L4.