猪脾脏酪氨酸蛋白激酶的研究

Studies on a Tyrosine Protein Kinase From Pig Spleen

采用DEAE-Sepharose CL-6B离子交换层析和Tyrosine-agarose亲和层析,首次从猪脾脏30000Xg颗粒中部分纯化了酪氨酸蛋白激酶,其比活性约为12000pmol.min^(-1).mg^(-1)。磷酸氨基酸分析表明,该酶能催化合成多肽poly(Glu.Ala.Tyr)_n(6:3:1)中的酪氨酸(Tyr)磷酸化,对该多肤废物和ATP的Km值分别约为2mg/mL和15μmol/L。Mn^(2+)对部分纯化的酪氨酸蛋白激酶的最大激活活性高于Mg^(2+),其AC_(50)分别约为1.4mmol/L和8mmol/L;发现红花素能强烈地抑制该酶活性,其IC_(50)约为125μmol/L。

Tyrosine protein kinase was partially purified from a 30000xg Partic-ulate fractions of pig spleen by DEAE-Sepharose CL-6B and tyrosine-agarose affinity columns. The specific activity of the partially purified kinase was about 12000 pmol. min-1mg-1. Poly(Glu.Ala.Thy)n(6:3:1) was phosphorylated by the partially purified kinase, and analysis of phosphoamino acid showed that only tyrosine was phosphory- lated in poly(Glu.Ala.Tyr)n(6:3:l) by the kinase with Km of 2mg/mL, and the Km for ATP was about 15μmol/L. The results indicated that the stimulation of Mn2+ on the tyrosine protein kinase was much higher than that of Mg2+. The AC50 of Mn2+ and Mg2+ were 1.4mmol/L and 8mmol/L, respectively. The tyrosine protein kinase was strongly inhibited by carthamidin and IC50 value was 125μmol/L.