脑髓鞘和胞质溶胶组分中髓鞘碱性蛋白的磷蛋白磷酸酶

Phosphoprotein phosphatases for myelin basic protein in myelin and cytosol fractions of brain.

作者信息

Miyamoto E, Kakiuchi S

出版信息

Biochim Biophys Acta. 1975 Apr 19;384(2):458-65. doi: 10.1016/0005-2744(75)90046-7.

Abstract

Phosphoprotein phosphatase (phosphoprotein phosphohydrolase EC 3.1.3.16) activity for myelin basic protein was found to be present in the myelin fraction of rat brain. The enzyme activity was in a latent form and solubilized by 0.2% Triton X-100 treatment with about 50% increase of activity. The cytosol fraction from bovine brain also had phosphoprotein phosphatase activity for myelin basic protein, which was resolved into at least two peaks of activity on DEAE-cellulose column chromatography. Myelin basic protein was the best substrate for both the solubilized myelin fraction and the cytosol enzymes among the substrate proteins tested. The Km values of the solubilized myelin fraction were 4.2 muM for myelin basic protein, 7.4 muM for arginine-rich histone, 8.0 muM for histone mixture and 14.3 muM for protamine, respectively.

摘要

已发现大鼠脑髓鞘部分存在针对髓鞘碱性蛋白的磷蛋白磷酸酶（磷蛋白磷酸水解酶，EC 3.1.3.16）活性。该酶活性呈潜伏形式，经0.2% Triton X-100处理后可溶解，活性增加约50%。牛脑的胞质溶胶部分也具有针对髓鞘碱性蛋白的磷蛋白磷酸酶活性，在DEAE-纤维素柱层析上可分解为至少两个活性峰。在所测试的底物蛋白中，髓鞘碱性蛋白是溶解的髓鞘部分和胞质溶胶酶的最佳底物。溶解的髓鞘部分针对髓鞘碱性蛋白的Km值分别为4.2 μM，针对富含精氨酸的组蛋白为7.4 μM，针对组蛋白混合物为8.0 μM，针对鱼精蛋白为14.3 μM。