Cloning and sequence analysis of rat hepsin, a cell surface serine proteinase.

A cDNA coding for the rat serine proteinase hepsin was isolated and its nucleotide sequence has been determined. The cDNA was 1739 nucleotides long and contained an open reading frame encoding a protein consisting of 416 amino-acid residues. The deduced amino-acid sequence of the rat enzyme was very similar to the human hepsin sharing an amino-acid sequence identity of 88.7%. Hydropathy plots reveal the presence of a short hydrophobic region close to the N-terminus believed to be a transmembrane domain which anchors the proteinase on the cell surface. The predicted sequence contains the His, Asp and Ser residues which make up the catalytic triad common to all serine proteinases.