5′-nucleotidase (ecto-5′-nucleotidase; CD73) (CD73)

5′-nucleotidase (CD73) is a glycosylphosphatidylinositol-anchored dimeric ectoenzyme, encoded by the NT5E gene, located on the external face of cell membranes, notably lymphocytes and endothelial cells. Its primary function is the hydrolysis of extracellular AMP to adenosine, which orchestrates a wide range of purinergic signaling pathways, particularly those controlling inflammation, vascular permeability, immune cell activation, and barrier function. CD73 is a critical regulator of immune homeostasis, limiting pro-inflammatory signals and generating anti-inflammatory adenosine, thus contributing both to protection in chronic inflammatory conditions and to immunosuppression in cancers and certain pathologies. Both membrane-bound and soluble forms exist, with the latter found in extracellular vesicles and body fluids, especially at sites of inflammation and cancer. CD73's catalytic pocket and conformational dynamics provide key pharmacological access points for therapeutic intervention, where inhibition can disrupt tumor-induced immune suppression but may also risk tissue dysfunction in organs dependent on CD73-mediated adenosine signaling.

Other names

Ecto-5′-nucleotidaseNT5E (gene symbol)5′-nucleotidase (sometimes written as 5'-nucleotidase)Cluster of differentiation 73

Inhibition of enzymatic activity, reducing adenosine production to promote anti-tumor immunity Antibody-mediated block of enzyme conformational change (prevents closed active state) Small-molecule inhibition of the catalytic pocket (competitive inhibition)