泌乳兔乳腺中酪蛋白激酶II的纯化与特性分析

Purification and characterization of casein kinase II from lactating rabbit mammary gland.

Mitev V, Pauloin A, Houdebine L M

Unité de Différenciation Cellulaire, Institute National de la Recherche Agronomique, Jouy-en Josas, France.

Int J Biochem. 1994 May;26(5):667-77. doi: 10.1016/0020-711x(94)90167-8.

Abstract

Highly purified 200 kDa casein kinase II from rabbit lactating mammary gland (MG-CK II) was obtained by means of a new purification procedure consisting of one phosphocellulose and three Monó Q steps. 2. Its Km for ATP was 2.22 microM and 0.57 mg/ml and 0.13 mg/ml for partially dephosphorylated casein and phosvitin respectively. Stathmine was also suitable as substrate. 2-aminopurine and 6-dimethylaminopurine inhibited efficiently MG-CK II (Ki = 5 and 1 mM respectively). 3. MG-CK II autophosphorylated on its alpha-, alpha'- and beta-subunits. The beta-subunit autophosphorylation was enhanced in presence of exogenous substrate. Its modulation was highly dependent on ATP concentration. 4. The effects of basic compounds which affected dramatically the phosphorylation of dephosphorylated casein in presence of various ATP concentrations were reported.

摘要

通过一种新的纯化方法获得了来自兔乳腺的高度纯化的200 kDa酪蛋白激酶II（MG-CK II），该方法包括一个磷酸纤维素步骤和三个Mono Q步骤。2. 其对ATP的Km值为2.22 microM，对部分去磷酸化的酪蛋白和磷蛋白的Km值分别为0.57 mg/ml和0.13 mg/ml。Stathmine也适合作为底物。2-氨基嘌呤和6-二甲基氨基嘌呤能有效抑制MG-CK II（Ki分别为5 mM和1 mM）。3. MG-CK II在其α-、α'-和β-亚基上进行自身磷酸化。在外源底物存在的情况下，β-亚基的自身磷酸化增强。其调节高度依赖于ATP浓度。4. 报道了在不同ATP浓度下，碱性化合物对去磷酸化酪蛋白磷酸化有显著影响的作用。