Taniguchi K, Suzuki K, Shimizu J, Iida S
J Biochem. 1980 Aug;88(2):609-12. doi: 10.1093/oxfordjournals.jbchem.a133010.
Na+,K+-ATPase [EC 3.6.1.3] from pig kidneys was treated with the fluorescent reagent N-(p-(2-benzimidazolyl)phenyl)maleimide (BIPM) in the presence of CKl. The resultant preparation showed 70% of the activity with only a small change in the apparent affinity for ligands of the enzyme. The addition of Na+ to the treated preparation induced a -2.1 +/- 0.1% change of the total fluorescence intensity observed in the absence of Na+. Further addition of both Mg2+ and ATP transiently increased the fluorescence to +0.5 +/- 0.1%. After the exhaustion of ATP, the fluorescence decreased to -3.1 +/- 0.1%. This cycle can be repeated by the readdition of ATP but not by ADP. Ouabain inhibits the fluorescence change. The ligands used reduced the fluorescence intensity as follows: Mg2+ + Na+ + ATP approximately K+, none, Mg2+ approximately ATP, Na+ + ATP, Na+ approximately Na+ + Mg2+, Na+ + Mg2+ + ADP approximately Na+ + ADP. The data indicate the presence of multiple conformational states of the enzyme.
猪肾来源的Na⁺,K⁺-ATP酶[EC 3.6.1.3]在CKl存在的情况下用荧光试剂N-(对-(2-苯并咪唑基)苯基)马来酰亚胺(BIPM)处理。所得制剂显示出70%的活性，而酶对配体的表观亲和力仅有微小变化。向处理后的制剂中添加Na⁺会导致在无Na⁺时观察到的总荧光强度发生-2.1±0.1%的变化。进一步添加Mg²⁺和ATP会使荧光瞬时增加至+0.5±0.1%。ATP耗尽后，荧光降至-3.1±0.1%。通过重新添加ATP可重复此循环，但添加ADP则不能。哇巴因抑制荧光变化。所使用的配体降低荧光强度的情况如下：Mg²⁺+Na⁺+ATP＞K⁺，无影响，Mg²⁺＞ATP，Na⁺+ATP，Na⁺＞Na⁺+Mg²⁺，Na⁺+Mg²⁺+ADP＞Na⁺+ADP。数据表明该酶存在多种构象状态。
