Ectonucleotide pyrophosphatase/phosphodiesterase family member 1 (PC-1, CD203a) is an enzyme that in humans is encoded by the ENPP1 gene.[5][6][7]
This gene is a member of the ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP) family. The encoded protein is a type II transmembrane glycoprotein comprising two identical disulfide-bonded subunits.
ENPP1 has broad specificity and cleaves a variety of substrates, including phosphodiester bonds of nucleotides and nucleotide sugars. ENPP1 protein may function to hydrolyze nucleoside 5′-triphosphates to their corresponding monophosphates and may also hydrolyze diadenosine polyphosphates.
The main substrate of ENNP1 is adenosine triphosphate (ATP), which is cleaved into adenosine monophosphate (AMP) and diphosphate.[8] Another notable nucleotide substrate is nicotinamide adenine dinucleotide (NAD+) which can be hydrolyzed to produce AMP.[8] ADPR can also be hydrolyzed by ENNP1 to produce AMP.[9]
Mutations in this gene have been associated with Generalized arterial calcification of infancy, ossification of the posterior longitudinal ligament of the spine (OPLL), Hypophosphatemic rickets autosomal recessive 2 (ARHR2), and insulin resistance.[6]
In a tumor microenvironment, AMP generated by ENNP1 can lead to production of adenosine, which suppresses the anti-cancer function of the immune system.[9][10][11]
Ectonucleotide pyrophosphatase/phosphodiesterase 1 has been shown to interact with Insulin receptor.[12]