Inhibitory effect of sulfhydryl group on Ca(2+)-ATPase activity in the plasma membrane-rich fraction from bovine parotid gland.
1. The present study demonstrated that the Ca(2+)-ATPase activity of the plasma membrane-rich fraction from bovine parotid gland was decreased by the addition of reducing agents. 2. Ca(2+)-ATPase activity staining on SDS-PAGE gels was lost in the presence of 2-mercaptoethanol. 3. Among all the reducing agents tested, GSH was the most effective in inhibiting Ca(2+)-ATPase. 4. The Ca(2+)-ATPase activity decreased by the GSH was restored by the addition of an oxidizing reagent. However, oxidation with an oxidizing reagent subsequent to alkylation of the reduced enzyme with iodoacetamide resulted in no restoration of activity. 5. The decrease of Ca(2+)-ATPase activity by GSH is due to a decrease in the Vmax of the enzyme. 6. These results suggest that the disulfide bond in this enzyme protein is necessary to maintain the activity of this enzyme.
Matsukawa
R
R
Department of Biochemistry, Nihon University School of Dentistry, Matsudo, Japan.
Cho
S J
SJ
Takiguchi
H
H
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D005978:Glutathione / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008623:Mercaptoethanol / Q000494:pharmacology; D010084:Oxidation-Reduction; D010306:Parotid Gland / Q000201:enzymology*; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000737:chemistry
D013438:Sulfhydryl Compounds; D008623:Mercaptoethanol; D000252:Calcium-Transporting ATPases; D005978:Glutathione