Enzymatic sulfation of mucus glycoprotein in gastric mucosa

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7170697

Liau, Y H; Carter, S R; Gwozdzinski, K; Nadziejko, C; Slomiany, A; Slomiany, B L

Among the posttranslational modifications that mucus glycoprotein undergo prior to secretion into the gastric lumen is the process of sulfation of the carbohydrate chains. These sulfate groups impart strongly negative charge to nucus glycoprotein and are thought to play a major role in the maintenance of gastric mucosal integrity. The authors report here the presence and some properties of an enzyme involved in the sulfation of gastric mucus glycoprotein. The sulfotransferase activity which catalyzes the transfer of sulfate ester group from PAPS to mucus glycoprotein was located in the detergent extracts of the microsomal fraction of rat gastric mucosa. Optimum enzymatic activity for sulfation of gastric mucin was obtained using 0.5% Triton X-100 and 25mM NaF at a pH of 6.8. ATP, ADP, MgCl/sub 2/ and MnCl/sub 2/ at concentrations examined were inhibitory. Under optimal conditions, the rate of sulfate incorporation was proportional to the microsomal enzyme protein concentration up to 50..mu..g and remained constant with time of incubation for at least 1h. The apparent Km value of the enzyme for gastric mucus glycoprotein was 8.3 x 10/sup -6/M. The /sup 35/S-labeled product of the enzyme reaction cochromatographed on Bio-Gel A-50 with gastric mucin, and gave on CsCl equilibrium density gradient centrifugation a band at the density of 1.48 in which the /sup 35/S label coincided with the glycoprotein.

• Research Organization: New York Medical College, Valhalla
• OSTI ID: 7170697
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADP
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
ATP
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CELL CONSTITUENTS
CHLORIDES
CHLORINE COMPOUNDS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
GASTROINTESTINAL TRACT
GLUCOPROTEINS
HALIDES
HALOGEN COMPOUNDS
INHIBITION
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAGNESIUM CHLORIDES
MAGNESIUM COMPOUNDS
MAMMALS
MEMBRANES
METABOLISM
MICROSOMES
MUCOUS MEMBRANES
NUCLEI
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PROTEINS
RADIOISOTOPES
RATS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
STOMACH
SULFUR 35
SULFUR ISOTOPES
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES