Napsins: new human aspartic proteinases - Distinction between two closely related genes

cDNA sequences were elucidated for two closely related human genes which en code the precursors of two hitherto unknown aspartic proteinases, The (pro) napsin A gene is expressed predominantly in lung and kidney and its transla tion product is predicted to be a fully functional, glycosylated aspartic p roteinase (precursor) containing an RGD motif and an additional 18 residues at its C-terminus. The (pro)napsin B gene is transcribed exclusively in ce lls related to the immune system but lacks an in-frame stop codon and conta ins a number of polymorphisms, one of which replaces a catalytically crucia l Gly residue with an Arg. Consideration is given to whether (pro)napsin B may be a transcribed pseudogene or whether its putative protein product und ergoes rapid intracellular degradation, (C) 1998 Federation of European Bio chemical Societies.