Role of N-linked oligosaccharides attached to human renin expressed in COS cells

Abstract

One or both of two putative N-glycosylation sites (at asparagine-5 and -75) of human renin was eliminated by amino acid replacement of the asparagine residue with an alanine residue using site-directed mutagenesis. The three glycosylation-deficient renins (Asn-5, Asn-75, Asn-S and -75 mutants) were expressed in COS cells and secreted into the conditioned media. The secreted amounts of the three mutants were different from one another, although the mutant and wildtype renins had practically the same specific activity. An Asn-5 and -75 mutant which did not contain any glycosylation sites was unstable in the medium, suggesting that the N-linked oligosaccharides play an important role in stabilization of human renin.