Multiple forms of phosphotyrosyl- and phosphoseryl-protein phosphatase from cardiac muscle: partial purification and characterization of an EDTA-stimulated phosphotyrosyl-protein phosphatase.
Multiple forms of phosphotyrosyl- and phosphoseryl-protein phosphatase from cardiac muscle: partial purification and characterization of an EDTA-stimulated phosphotyrosyl-protein phosphatase.
复制标题
来自心肌的多种形式的磷酸酪氨酰和磷酸丝氨酰蛋白磷酸酶：EDTA 刺激的磷酸酪氨酰蛋白磷酸酶的部分纯化和表征。
DOI：
10.1016/0003-9861(83)90321-1
复制
发表时间：
1983
影响因子：
3.9
通讯作者：
Li,HC
中科院分区：
文献类型：
--
作者：
Chernoff,J;Li,HC
心肌和脑提取物在deae -纤维素上的色谱将磷酸酪氨酸蛋白磷酸酶活性分解为三个部分，称为Y-1， Y-2和Y-3。以0.05、0.15和0.3mKCl洗脱，分别占树脂酶活性的33%、55%和12%。对比研究表明，Y-1、Y-2和Y-3磷酸酶的性质与先前鉴定的磷酸丝氨酸蛋白磷酸酶-1、-2、-3和-4有明显不同。磷酸酶Y-1、Y-2和Y-3受到EDTA的刺激，在中性ph下表现出最佳活性。这些特性不同于与磷酸丝氨酸蛋白磷酸酶-3和-4相关的两种次要磷酸酪氨酸蛋白磷酸酶的活性，它们是二价阳离子依赖性的，在碱性ph下表现出最佳活性。酶的aMr= 65,000 （Stokes半径= 3.8 nm;s20,w0= 4.1）。EDTA （Ka= 15 μM）对其活性有5 ~ 10倍的刺激，而钒酸盐则对其活性有较强的抑制作用。磷酸酶Y-2对磷酪氨酸- igg和-酪蛋白具有高度特异性，对磷酪氨酸-酪蛋白、-磷酸化酶、磷苏酰-抑制剂-1和对硝基苯磷酸活性较弱。目前的研究表明，磷酸酪氨酸蛋白磷酸酶在动物组织中的活性存在多种形式。主要活性种是针对磷酸酪氨酸蛋白的，代表不同于已知的磷酸丝氨酸蛋白磷酸酶和对硝基苯基磷酸酶的酶。
Chromatography of cardiac muscle and brain extracts on DEAE-cellulose resolved phosphotyrosyl-protein phosphatase activity into three fractions, termed Y-1, Y-2 and Y-3. These were eluted at 0.05, 0.15 and 0.3mKCl, representing about 33, 55 and 12%, respectively, of the enzymatic activity recovered from the resin. Comparative studies demonstrated that the properties of phosphatases Y-1, Y-2 and Y-3 were distinctly different from those of previously identified phosphoseryl-protein phosphatases-1, -2, -3, and -4. Phosphatases Y-1, Y-2 and Y-3 were stimulated by EDTA and exhibited optimal activity at neutral pH. These properties were different from those of the two minor phosphotyrosyl-protein phosphatase activities associated with phosphoseryl-protein phosphatases-3, and -4, which were divalent cation dependent and exhibited optimal activity at alkaline pH. Further purification of phosphatase Y-2 from bovine heart has been carried out. The enzyme had aMr= 65,000 (Stokes radius = 3.8 nm;s20,w0= 4.1). Its activity was stimulated by 5- to 10-fold in the presence of EDTA (Ka= 15 μM) and was strongly inhibited by micromolar concentrations of vanadate. Phosphatase Y-2 was highly specific for phosphotyrosyl-IgG and -casein, and showed little activity toward phosphoseryl-casein, -phosphorylasea, phosphothreonyl-inhibitor-1 andp-nitrophenyl phosphate. The present studies indicate that phosphotyrosyl-protein phosphatase activity in animal tissues exists in multiple forms. The major active species are specific for phosphotyrosyl proteins and represent enzymes different from the known phosphoseryl-protein phosphatases andp-nitrophenyl phosphatases.