Gruppuso P A, Shriner C L, Brautigan D L
Division of Biology and Medicine, Brown University, Providence, RI 02912.
Biochem Biophys Res Commun. 1987 Nov 13;148(3):1174-81. doi: 10.1016/s0006-291x(87)80256-5.
We have examined the characteristics of partially purified forms of rabbit skeletal muscle type-1 protein phosphatase (PP-1). Over 90% of PP-1 in unfractionated extracts and in glycogen particles was inactive, but could be activated by the divalent cations, Mn2+ or Co2+ (Me2+) plus trypsin. Gel filtration of muscle extracts revealed two inactive forms of PP-1; one activated by Me2+ alone or Me2+ plus trypsin, and a second containing inhibitor-2 and activated only by Me2+ plus trypsin. The kinetics of Me2+ plus trypsin activation revealed that after DEAE-chromatography, PP-1 was altered from the forms in crude extracts, gel filtered extracts or glycogen particles. The results indicate that the purified form of PP-1 catalytic subunit has properties which distinguish it from the forms of the enzyme in muscle extracts.
我们已经研究了兔骨骼肌1型蛋白磷酸酶（PP-1）部分纯化形式的特性。未分级提取物和糖原颗粒中超过90%的PP-1是无活性的，但可被二价阳离子Mn2+或Co2+（Me2+）加胰蛋白酶激活。对肌肉提取物进行凝胶过滤显示出PP-1的两种无活性形式；一种仅被Me2+或Me2+加胰蛋白酶激活，另一种含有抑制剂2且仅被Me2+加胰蛋白酶激活。Me2+加胰蛋白酶激活的动力学表明，经过DEAE柱层析后，PP-1与粗提取物、凝胶过滤提取物或糖原颗粒中的形式有所不同。结果表明，PP-1催化亚基的纯化形式具有一些特性，使其有别于肌肉提取物中该酶的形式。
