ENPP4 (Ectonucleotide Pyrophosphatase/Phosphodiesterase 4): ENPP4 is a member of the ectonucleotide pyrophosphatase/phosphodiesterase (ENPP) family of enzymes, which play important roles in purinergic signaling and phosphate homeostasis. ENPP4 specifically functions as both a phosphodiesterase, catalyzing the hydrolysis of phosphodiester bonds, and a pyrophosphatase, cleaving pyrophosphate bonds. It is predominantly expressed in tissues such as the kidney, liver, and brain, where it participates in various physiological processes including bone mineralization, lipid metabolism, and regulation of extracellular nucleotide levels. ENPP4 has also been implicated in modulating immune responses and inflammation through its interaction with purinergic receptors. Dysregulation of ENPP4 activity has been associated...