Li H C, Chernoff J, Chen L B, Kirschonbaum A
Eur J Biochem. 1984 Jan 2;138(1):45-51. doi: 10.1111/j.1432-1033.1984.tb07879.x.
Using [32P]P-Tyr-IgG and [32P]P-Tyr-casein phosphorylated by pp60v-src as substrates, studies on the phosphotyrosyl-protein phosphatase activity in human prostate gland indicate that it is associated with prostatic acid phosphatase. Evidence to support this conclusion include the following: (a) these two enzymatic activities co-purify to apparent homogeneity; (b) they co-migrated on polyacrylamide gel electrophoresis, ion-exchange and gel filtration chromatographies; (c) the exhibit identical thermostability; and (d) the phosphotyrosyl-protein phosphatase activity is sensitive to inhibition by p-nitrophenyl phosphate and by several classical inhibitors of prostatic acid phosphatase including L(+)-tartrate, molybdate, vanadate and NaF. The purified enzyme exhibits high specificity towards phosphotyrosyl-proteins with little activity towards several phosphoseryl-proteins and phosphothreonyl-proteins examined. The present findings indicate that prostatic acid phosphatase may function in vivo as a phosphotyrosyl-protein phosphatase.
以经pp60v-src磷酸化的[32P]P-酪氨酸-免疫球蛋白G和[32P]P-酪氨酸-酪蛋白作为底物，对人前列腺中磷酸酪氨酸蛋白磷酸酶活性的研究表明，它与前列腺酸性磷酸酶相关。支持这一结论的证据如下：（a）这两种酶活性共同纯化至表观均一性；（b）它们在聚丙烯酰胺凝胶电泳、离子交换和凝胶过滤色谱上共同迁移；（c）它们表现出相同的热稳定性；（d）磷酸酪氨酸蛋白磷酸酶活性对磷酸对硝基苯酯以及几种前列腺酸性磷酸酶的经典抑制剂（包括L(+)-酒石酸盐、钼酸盐钒酸盐和氟化钠）的抑制敏感。纯化后的酶对磷酸酪氨酸蛋白具有高度特异性，而对所检测的几种磷酸丝氨酸蛋白和磷酸苏氨酸蛋白活性很低。目前的研究结果表明，前列腺酸性磷酸酶在体内可能作为磷酸酪氨酸蛋白磷酸酶发挥作用。
