Two transcript variants encoding different isoforms have been found for this gene. Variant 1 represents the longer transcript and encodes the longer isoform 1, 9 exons, transcript length 3548 bps, translation length 574 residues; variant 2 lacks an alternate in-frame exon compared to variant 1, 8 exons, transcript length 3384 bps, translation length 524 residues.

There are two isoforms of NT5E. 5-nucleotidase isoform 1 preproprotein, 574 amino acids; 5-nucleotidase isoform 2 preproprotein, 524 amino acids. Isoform 2 has the same N- and C-termini but is shorter compared to isoform 1.
The NT5E preproprotein is further processed into a mature form, which consists of a dimer of 2 identical 70-kD subunits bound by a glycosyl phosphatidyl inositol linkage at its C-terminus to the external face of the plasma membrane.

CD73 is a cell surface enzyme found in most tissues and many cell types including subsets of lymphocytes, macrophages, dendritic cells, endothelial cells and epithelial cells. Hypoxia induces CD73 mRNA, protein expression and increases CD73 activity in mouse microvascular endothelial cells. Particularly, CD73 is highly expressed in many human solid tumors, and its elevated expression and activity are associated with tumor invasiveness and metastasis and with shorter patient survival. The RNA expression and enzyme activity of CD73 are variable in different breast cancer cell lines. For more details see gene expression pattern of NT5E.

Plasma membrane.

CD73 is an ectoenzyme (ecto-50-nucleotidase, EC 3.1.3.5). It catalyzes conversion of AMP to adenosine. Adenosine exerts its effects via adenosine receptor A1, adenosine receptor A2A, adenosine receptor A2B and adenosine receptor A3.
CD73 has many physiological roles, such as regulation of barrier function, adaptation to hypoxia, ischemic preconditioning, anti-inflammation, leukocyte extravasation.
Expression and activity of CD73 on cancer cells is associated with poor prognosis and may promote metastasis. CD73 facilitates the adhesion, migration, invasion of human breast cancer cells and proliferation of glioma cells and these process are dependent upon the enzymes production of adenosine.