Saks V A, Lipina N V, Sharov V G, Smirnov V N, Chazov E, Grosse R
Biochim Biophys Acta. 1977 Mar 17;465(3):550-8. doi: 10.1016/0005-2736(77)90272-3.
A rat heart plasma membrane preparation isolated in a sucrose medium and some of its enzymatic properties have been investigated. It has been shown that a rat heart plasma membrane fraction contains high creatine phosphokinase activity which can not be diminished by repeated washing with sucrose solution. Creatine phosphokinase extracted from a plasma membrane fraction with potassium chloride and 0.01% deoxycholate solution is electrophoretically identical to MM isoenzyme of creatine phosphokinase. Under the conditions where (Na+,K+)-ATPase is activated by addition of Na+, K+ and MgATP, creatine phosphokinase of plasma membrane fraction is able to maintain a low ADP concentration in the medium if creatine phosphate is present. The rate of creatine release is dependent upon MgATP concentration in accordance with the kinetic parameters of the (Na+,K+)-ATPase and is significantly inhibited by ouabain (0.5 mM). The rate of creatine release is also dependent on creatine phosphate concentration in conformance with the kinetic parameters of MM isozyme of creatine phosphokinase. It is concluded that in intact heart cells the plasma membrane creatine phosphokinase may ensure effective utilization of creatine phosphate for immediate rephosphorylation of ADP produced in the (Na+,K+)-ATPase reaction.
已对在蔗糖培养基中分离得到的大鼠心脏质膜制剂及其一些酶学性质进行了研究。结果表明，大鼠心脏质膜部分含有高活性的肌酸磷酸激酶，用蔗糖溶液反复洗涤也不能使其活性降低。用氯化钾和0.01%脱氧胆酸盐溶液从质膜部分提取的肌酸磷酸激酶在电泳上与肌酸磷酸激酶的MM同工酶相同。在通过添加Na⁺、K⁺和MgATP激活（Na⁺,K⁺）-ATP酶的条件下，如果存在磷酸肌酸，质膜部分的肌酸磷酸激酶能够维持培养基中低浓度的ADP。肌酸释放速率取决于MgATP浓度，符合（Na⁺,K⁺）-ATP酶的动力学参数，并被哇巴因（0.5 mM）显著抑制。肌酸释放速率还取决于磷酸肌酸浓度，符合肌酸磷酸激酶MM同工酶的动力学参数。得出的结论是，在完整的心脏细胞中，质膜肌酸磷酸激酶可确保磷酸肌酸有效用于（Na⁺,K⁺）-ATP酶反应中产生的ADP的即时再磷酸化。
