Oxidative inhibition of Ca2+-ATPase in the rabbit lens.
Hydrogen peroxide inhibition of maximum Ca2+-ATPase and Na+,K+-ATPase activity was measured in a membrane-enriched preparation of rabbit lens cortical fibers and epithelium. At 5 X 10(-6) M hydrogen peroxide maximum Ca2+-ATPase activity was inhibited by 39%, while maximum Na+,K+-ATPase activity was stimulated. Ca2+-ATPase activity was almost completely inhibited at 5 X 10(-4) M hydrogen peroxide, in comparison to Na+,K+-ATPase activity, which was only inhibited by 28% at a concentration of hydrogen peroxide an order of magnitude larger. The addition of catalase to hydrogen peroxide-pretreated samples did not reverse the inhibition of Ca2+-ATPase by hydrogen peroxide.
Borchman
D
D
Department of Ophthalmology, University of Louisville School of Medicine, Kentucky Lions Eye Research Institute, Kentucky 40202.
Paterson
C A
CA
Delamere
N A
NA
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004848:Epithelium / Q000201:enzymology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007904:Lens Cortex, Crystalline / Q000201:enzymology; D007908:Lens, Crystalline / Q000201:enzymology*; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis / Q000378:metabolism*
D006861:Hydrogen Peroxide; D002374:Catalase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase