H2O2-induced uncoupling of bovine lens Na+,K+-ATPase

摘要: Abstract A 1-hr exposure of bovine lenses in organ culture to H2O2 concentrations the range found aqueous fluid patients with cataracts inhibits 86Rb+ influx. At 1 mM H2O2, complete inhibition was observed and further investigated. Membrane permeability is slightly decreased. Although lactate increase 2-fold, lens ATP decrease approximately equal 10%, suggesting that glycolysis may be stimulated but production not able keep up demand for energy. Examination epithelial cell Mg2+-stimulated Na+,K+-ATPase isolated from cultured indicates H2O2-induced modification. 5 MgATP, hydrolysis accelerated 30%; at 3 normal; 0.75 it inhibited 75%. p-Nitrophenyl phosphate eosin maleimide binding indicate K+ control enzyme modified. Thus, a very early effect upon lens, well before formation opacity, appears uncoupling Na+ transport hydrolysis.