NAPSA Human

Napsin A Aspartic Peptidase, commonly referred to as Napsin A, is a member of the peptidase A1 family of aspartic proteases. This enzyme is encoded by the NAPSA gene and is predominantly expressed in the lung and kidney tissues . Napsin A plays a crucial role in the proteolytic processing of pulmonary surfactant protein B and protein catabolism in the renal proximal tubules .

The NAPSA gene is located on chromosome 19q13.33 in humans . The gene encodes a preproprotein that undergoes proteolytic processing to generate an activation peptide and the mature protease . The mature enzyme is a glycosylated aspartic protease with a molecular weight of approximately 38 kDa . The enzyme contains a signal peptide, an activation peptide, and a mature enzyme domain .

Napsin A is involved in the processing of pneumocyte surfactant precursors, which are essential for lung function . The activation peptides of aspartic proteinases, including Napsin A, function as inhibitors of the protease active site. These peptide segments are important for the correct folding, targeting, and control of the activation of aspartic proteinase zymogens .

Napsin A has been identified as a useful biomarker for the diagnosis of primary lung adenocarcinoma and renal cell carcinoma . Its expression can help distinguish adenocarcinomas from other forms of lung cancer . Additionally, Napsin A is associated with diseases such as Renal Wilms’ Tumor and Myoblastoma .

Recombinant Napsin A is produced using recombinant DNA technology, which involves inserting the NAPSA gene into an expression system to produce the protein in vitro. This recombinant form is used in various research and diagnostic applications to study its function and role in diseases .