Role of N-glycosylation in human angiotensinogen

J Biol Chem. 1998 Aug 14;273(33):21232-8. doi: 10.1074/jbc.273.33.21232.


Human angiotensinogen, the specific substrate of renin, is a heterogeneous glycoprotein constitutively secreted by the liver. Different glycosylation levels may be responsible for its heterogeneity. It contains four putative asparagine-linked glycosylation sites (Asn-X-Ser/Thr). Systematic site-directed mutagenesis (Asn replaced with Gln) of these four sites was undertaken, and 11 (single, double, triple, and quadruple (N-4)) mutants were produced in COS-7 and/or CHO-K1 cells and characterized. All of the sites were N-glycosylated with preferential glycosylation of the Asn14 and the Asn271. The suppression of the Asn14 glycosylation site led to 5 times lower Km and a 10 times lower kcat. Angiotensinogen heterogeneity was much lower for the N-4 mutant protein, which produced a single form at 48 kDa. Pulse-chase experiments showed slight intracellular retention (15%) of the deglycosylated protein after 24 h. Interestingly, the N-4 mutant had a higher catalytic efficiency (kcat/Km = 5.0 versus 1.6 microM-1 . s-1) than the wild-type protein. The thermal stability of the N-4 protein was unaffected by deglycosylation, suggesting that it was correctly folded. This deglycosylated recombinant human angiotensinogen could be of value for x-ray crystallography studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensinogen / genetics
  • Angiotensinogen / metabolism*
  • Animals
  • Base Sequence
  • Biological Transport
  • CHO Cells
  • COS Cells
  • Cloning, Molecular
  • Cricetinae
  • DNA, Complementary
  • Glycosylation
  • Hot Temperature
  • Humans
  • Kinetics
  • Mutagenesis, Site-Directed
  • Oligonucleotides, Antisense
  • Recombinant Proteins / metabolism
  • Renin / metabolism


  • DNA, Complementary
  • Oligonucleotides, Antisense
  • Recombinant Proteins
  • Angiotensinogen
  • Renin