【摘要】 本文采用离子交换柱层析、硫酸铵盐析、亲和层析等方法,从牛心肌中提取、纯化了肌球蛋白轻链激酶（MLCK）,酶的比活性为12nmolPi/mg Min^-1.提纯倍数为499倍,对底物ATP的km值为220μmol/L,MLCK为Ca²⁺、钙调蛋白依赖性酶,在EGTA存在时,激酶无活性。同时还发现.低Mg²⁺浓度时.MLCK 活性升高.高Mg²⁺（4.5mmol/L以上）时,MLCK活性反而下降。更多还原

【Abstract】 MLCK had been purified from bovine cardiac muscles approx . 499-fold by (NH4 )2SO4 fractionation,ion-ex nge and affinity chromatography. Its activity was 12nmol Pi/mg min-1. The enzyme exhibited a km for f 220μmol/L. The isolated kinase was active only as a ternary complex consisting of the kinase. lin,and Ca2+. In the presence of EGTA,it w nactive. The activity of MLCK would be decreased gh concentration of Mg2+ (>4. 5mmol/L ).更多还原