Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Biosynthesis of gastric mucus glycoprotein of the rat

Journal Article · · J. Biol. Chem.; (United States)
OSTI ID:5768385

We have studied the biosynthesis of rat gastric mucin in stomach segments using an antiserum against rat gastric mucin specific for peptide epitopes. Pulse-chase experiments were performed with (/sup 35/S)methionine, (/sup 3/H)galactose, and (/sup 35/S)sulfate to label mucin precursors in different stages of biosynthesis, which were analyzed after immunoprecipitation. The earliest mucin precursor that could be detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was a 300-kDa protein. The occurrence of N-linked high-mannose oligosaccharides on this protein was shown by susceptibility to degradation by endo-beta-N-acetylglucosaminidase H. This precursor could be labeled with (/sup 35/S)methionine and not with (/sup 3/H)galactose or (/sup 35/S)sulfate. The 300-kDa precursor was converted into mature mucin after extensive glycosylation and sulfation. The mature mucin but not the 300-kDa precursor was in part secreted into the medium. Specific inhibition of sulfation with sodium chlorate had no effect on rate and amount of mucin secretion. In addition, we show that two core proteins are expressed in rats, slightly varying in Mr among individual animals.

Research Organization:
State Univ. of Utrecht (Netherlands)
OSTI ID:
5768385
Journal Information:
J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 264:18; ISSN JBCHA
Country of Publication:
United States
Language:
English