H2O2-INDUCED UNCOUPLING OF BOVINE LENS NA+,K+-ATPASE
H2O2-INDUCED UNCOUPLING OF BOVINE LENS NA+,K+-ATPASE
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DOI：
10.1073/pnas.80.7.2044
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发表时间：
1983-01-01
期刊：
影响因子：
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通讯作者：
SPECTOR, A
中科院分区：
文献类型：
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作者：
GARNER, WH;GARNER, MH;SPECTOR, A
在白内障患者的房水中发现的范围内的H2O2浓度的牛晶状体在器官培养中暴露1小时抑制86Rb+流入。在1 mM H2O2下，观察到完全抑制并进一步研究。膜通透性略有下降。虽然乳酸盐浓度增加2倍，但透镜ATP浓度降低约10%，这表明糖酵解可能被刺激，但ATP的产生无法跟上对能量的需求。从培养的晶状体中分离的上皮细胞Mg~（2+）刺激的Na~+，K~+-ATP酶的检查表明H_2O_2诱导的修饰。在5 mM MgATP时，ATP水解加速30%，在3 mM MgATP时，水解正常;在0.75 mM MgATP时，抑制75%。对硝基苯基磷酸水解和曙红马来酰亚胺结合表明，K+控制的酶被修改。H2O2对透镜的一个非常早期的影响，在混浊形成之前，似乎是ATP水解的Na+和K+转运的解偶联。
A 1 h exposure of bovine lenses in organ culture to H2O2 concentrations in the range found in the aqueous fluid of patients with cataracts inhibits 86Rb+ influx. At 1 mM H2O2, complete inhibition was observed and further investigated. Membrane permeability was slightly decreased. Although lactate concentrations increase 2-fold, lens ATP concentrations decrease .apprxeq. 10%, suggesting that glycolysis may be stimulated but ATP production is not able to keep up with the demand for energy. Examination of epithelial cell Mg2+-stimulated Na+, K+-ATPase isolated from the cultured lenses indicates H2O2-induced modification. At 5 mM MgATP, ATP hydrolysis is accelerated 30%, at 3 mM MgATP, hydrolysis was normal; and at 0.75 mM MgATP, it is inhibited 75%. p-Nitrophenyl phosphate hydrolysis and eosin maleimide binding indicate that K+ control of the enzyme is modified. A very early effect of H2O2 upon the lens, well before the formation of opacity, appears to be the uncoupling of Na+ and K+ transport from ATP hydrolysis.