Enzymatic sulfation of gastric mucous glycoprotein in rat--changes in glycoprotein sulfotransferase activity with stress and anti-ulcer agent, sofalcone.
Enzymatic sulfation of mucous glycoprotein (GP) was studied in gastric mucosa of rat. After rat stomach was incubated with [35S]-sulfate, incorporation of radioactivity into gastric mucosal APS (adenosine 5'-phosphosulfate), PAPS (3'-phosphoadenosine 5'-phosphosulfate) and endogenous GPs could be detected. The degree of sulfation of endogenous GPs was highest in the macromolecular GP (peak I) and lowest in the low molecular GP (peak III). By using a crude preparation of GP sulfotransferase from rat gastric mucosa, the transfer of [35S]-sulfate from [35S]-PAPS into macromolecular mucous GP was determined as being the activity of sulfotransferase. The activity of GP sulfotransferase was mainly distributed in the microsomal fraction, and was proportional to the incubation time, substrate (mucous GP) concentration and [35S]-PAPS concentration. The enzyme activity was significantly higher in the corpus than that in the antral mucosa. The activity of GP sulfotransferase was significantly decreased at 6 h and was significantly increased at 12 h after the stress load, compared with that of the non-stressed condition. Anti-ulcer agent, sofalcone, increased the GP sulfotransferase activity under the stressed condition. On the other hand, cimetidine showed a significant inhibitory effect under the same condition. Changes in the GP sulfotransferase activity with stress and anti-ulcer agents were consistent with those in the incorporation of [35S]-sulfate into macromolecular mucous GP. These results suggest the importance of GP sulfotransferase as a key enzyme regulating the sulfation of mucous GP.
D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D002599:Chalcone / Q000031:analogs & derivatives / Q000494:pharmacology*; D047188:Chalcones; D002803:Chondro-4-Sulfatase / Q000378:metabolism; D005753:Gastric Mucosa / Q000201:enzymology* / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D008297:Male; D011427:Propiophenones / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013315:Stress, Psychological / Q000201:enzymology* / Q000378:metabolism; D015238:Sulfotransferases; D013462:Sulfur Radioisotopes; D013466:Sulfurtransferases / Q000378:metabolism*
D000897:Anti-Ulcer Agents; D047188:Chalcones; D006023:Glycoproteins; D011427:Propiophenones; D013462:Sulfur Radioisotopes; C035032:sofalcone; D002599:Chalcone; D013466:Sulfurtransferases; D015238:Sulfotransferases; C042860:glycoprotein sulfotransferase; D002803:Chondro-4-Sulfatase