Pardo P, Moreno S
Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
Second Messengers Phosphoproteins. 1988;12(4):183-96.
Two cyclic-nucleotide independent soluble casein kinase activities (CK I and CK II) from the fungus Mucor rouxii have been isolated, characterized and found to fit in the general classification of type 1 (CK I) and 2 (CK II) casein kinases, according to their enzymatic and structural properties. Both enzymes phosphorylate acidic substrates, require Mg2+ and have a chromatographic behaviour on DEAE-Sepharose and phosphocellulose similar to their mammalian counterparts. CK I has a sedimentation coefficient of 3.5 S, uses ATP as a phosphate donor (Km = 40 microM), phosphorylates casein mainly on serine residues, its activity is strongly inhibited by KCl and polyamines. CK II has a sedimentation coefficient of 7.4 S, uses ATP and GTP as phosphate donors (Km ATP = 10 microM; Km GTP = 40 microM), phosphorylates casein in serine and threonine, its activity is stimulated by KCl and by polyamines and is inhibited by heparin (I50 = 0.5 micrograms/ml). Casein kinase activity associated to particulate fraction (40% of total) has been partially characterized and shown to be similar to the soluble CK I activity.
已从鲁氏毛霉中分离出两种不依赖环核苷酸的可溶性酪蛋白激酶活性物质（酪蛋白激酶I和酪蛋白激酶II），并对其进行了表征，根据其酶学和结构特性，发现它们符合1型（酪蛋白激酶I）和2型（酪蛋白激酶II）酪蛋白激酶的一般分类。这两种酶均能磷酸化酸性底物，需要Mg2+，并且在DEAE-琼脂糖和磷酸纤维素上的色谱行为与其哺乳动物对应物相似。酪蛋白激酶I的沉降系数为3.5 S，以ATP作为磷酸供体（Km = 40 microM），主要在丝氨酸残基上磷酸化酪蛋白，其活性受到KCl和多胺的强烈抑制。酪蛋白激酶II的沉降系数为7.4 S，以ATP和GTP作为磷酸供体（Km ATP = 10 microM；Km GTP = 40 microM），在丝氨酸和苏氨酸上磷酸化酪蛋白，其活性受到KCl和多胺的刺激，并受到肝素的抑制（I50 = 0.5微克/毫升）。与颗粒部分相关的酪蛋白激酶活性（占总量的40%）已得到部分表征，显示与可溶性酪蛋白激酶I活性相似。
