Isolation and characterization of an inhibitor-sensitive and a polycation-stimulated protein phosphatase from rat liver nuclei.
Isolation and characterization of an inhibitor-sensitive and a polycation-stimulated protein phosphatase from rat liver nuclei.
复制标题
从大鼠肝细胞核中分离和表征抑制剂敏感的和聚阳离子刺激的蛋白磷酸酶。
DOI：
10.1016/0167-4889(86)90079-0
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Schlender,KK
中科院分区：
文献类型：
--
作者：
Jakes,S;Mellgren,RL;Schlender,KK
从大鼠肝细胞核中分离到两种蛋白磷酸酶。用1 M NaCl从粗染色质中溶解的酶，通过Sephadex G-150、DEAE-Sepharose和肝素-Sepharose柱层析解析。磷酸化酶磷酸酶活性的酶之一（底物敏感性磷酸酶）抑制热稳定的磷酸酶抑制剂蛋白，也由组蛋白H1。该磷酸酶的分子量约为。4 M尿素处理前后均为35000。其活性对磷酸化酶激酶β亚基具有特异性。用0.1 mM ATP预处理仅抑制酶约10%，并且其活性不需要二价阳离子。根据这些性质，这种核酶被鉴定为磷酸酶1的催化亚基。另一种磷酸酶（聚阳离子刺激的磷酸酶）对抑制剂1的抑制不敏感，低浓度组蛋白H1（A0.5= 0.6μM）可刺激10倍。该酶的分子量约为。70000人，减少到约。用4 M尿素处理后35 000。它使磷酸化酶激酶的α-和β-亚基去磷酸化。该酶被抑制90%以上的预孵育与0.1 mM ATP，并不需要二价阳离子的活性。根据这些性质，这种核酶被鉴定为磷酸酶2A。
Two protein phosphatases were isolated from rat liver nuclei. The enzymes, solubilized from crude chromatin by 1 M NaCl, were resolved by column chromatography on Sephadex G-150, DEAE-Sepharose and heparin-Sepharose. The phosphorylase phosphatase activity of one of the enzymes (inhibitor-sensitive phosphatase) was inhibited by heat-stable phosphatase inhibitor proteins and also by histone H1. This phosphatase had a molecular weight of approx. 35 000 both before and after 4 M urea treatment. Its activity was specific for the β-subunit of phosphorylase kinase. Pretreatment with 0.1 mM ATP inhibited the enzyme only about 10%, and it did not require divalent cations for activity. On the basis of these properties, this nuclear enzyme was identified as the catalytic subunit of phosphatase 1. The other phosphatase (polycation-stimulated phosphatase) was insensitive to inhibition by inhibitor 1, and it was stimulated 10-fold by low concentrations of histone H1 (A0.5= 0.6μM). This enzyme had a molecular weight of approx. 70 000 which was reduced to approx. 35 000 after treatment with 4 M urea. It dephosphorylated both the α- and β-subunits of phosphorylase kinase. The enzyme was inhibited more than 90% by preincubation with 0.1 mM ATP and did not require divalent cations for activity. On the basis of these properties, this nuclear enzyme was identified as phosphatase 2A.