Schlender K K, Wilson S E, Mellgren R L
Biochim Biophys Acta. 1986 Jul 25;872(1-2):1-10. doi: 10.1016/0167-4838(86)90140-8.
The predominant form of phosphorylase phosphatase activity in porcine renal cortical extracts was a polycation-stimulated protein phosphatase. This activity was present in extracts in a high-molecular-weight form which could be converted to a free catalytic subunit by treatment with ethanol, urea, or freezing and thawing in the presence of beta-mercaptoethanol. The catalytic subunit of the polycation-stimulated phosphatase was purified by chromatography on DEAE-Sephacel, heparin-Sepharose, and Sephadex G-75. The phosphatase appeared to be homogeneous on SDS-polyacrylamide gel electrophoresis. The enzyme had an apparent Mr of 35 000 on gel filtration and SDS-polyacrylamide gel electrophoresis. The purified phosphatase could be stimulated by histone H1, protamine, poly(D-lysine), poly(L-lysine) or polybrene utilizing phosphorylase a as the substrate. It preferentially dephosphorylated the alpha-subunit of phosphorylase kinase. The phosphatase was highly sensitive to inhibition by ATP. These results suggest that the renal polycation-stimulated phosphatase catalytic subunit is very similar to or identical with the skeletal muscle phosphatase form which has been previously designated phosphatase-2Ac.
猪肾皮质提取物中磷酸化酶磷酸酶活性的主要形式是一种多阳离子刺激的蛋白磷酸酶。这种活性以高分子量形式存在于提取物中，通过用乙醇、尿素处理，或在β-巯基乙醇存在下冻融，可转化为游离催化亚基。多阳离子刺激的磷酸酶的催化亚基通过在DEAE-葡聚糖凝胶、肝素-琼脂糖凝胶和葡聚糖G-75上进行层析而得以纯化。在SDS-聚丙烯酰胺凝胶电泳上，该磷酸酶似乎是均一的。在凝胶过滤和SDS-聚丙烯酰胺凝胶电泳上，该酶的表观分子量为35000。利用磷酸化酶a作为底物，纯化的磷酸酶可被组蛋白H1、鱼精蛋白、聚（D-赖氨酸）、聚（L-赖氨酸）或聚凝胺刺激。它优先使磷酸化酶激酶的α亚基去磷酸化。该磷酸酶对ATP抑制高度敏感。这些结果表明，肾多阳离子刺激的磷酸酶催化亚基与先前被命名为磷酸酶-2Ac的骨骼肌磷酸酶形式非常相似或相同。
