Teraoka H, Mizuta K, Sato F, Shimoyachi M, Tsukada K
Eur J Biochem. 1975 Oct 15;58(2):297-302. doi: 10.1111/j.1432-1033.1975.tb02376.x.
A polynucleotide kinase, which catalyzes the phosphorylation of 5'-hydroxyl ends of deoxyribonucleic acid in the presence of adenosine triphosphate, has been purified 260-fold with a yield of 14% from 0.15 M NaCl extracts of rat liver nuclei. The purified enzyme has a pH optimum of 5.5. The enzyme is reversible inhibited by p-chloromercuribenzoate. The S0.5 value (ligand concentration required for a half-maximal activity) for ATP is 2.5 muM. A bivalent cation is essential for the reaction and S0.5 values for Mg2+, Ca2+ and Mn2+ are 3.3 mM, 4 mM and 0.05 mM respectively. Pyrophosphate remarkable inhibits the activity with I0.5 value (ligand concentration required for a half-maximal inhibition) of 0.2 mM, and sulfate, with I0.5 of 0.5 mM, whereas phosphate weakly inhibits the activity with I0.5 of about 20 mM. An apparent molecular weight of the purified enzyme is estimated to be 8 X 10(4) by gel filtration on a column of Sephadex G-150, and the Stokes radius of the enzyme molecule is shown to be about 0.36 nm. Sucrose density gradient centrifugation reveals that the enzyme has a sedimentation coefficient of about 4.4 S.
一种多核苷酸激酶在三磷酸腺苷存在的情况下催化脱氧核糖核酸5'-羟基末端的磷酸化反应。该酶已从大鼠肝细胞核的0.15M氯化钠提取物中纯化了260倍，产率为14%。纯化后的酶最适pH值为5.5。该酶可被对氯汞苯甲酸可逆抑制。ATP的S0.5值（达到最大活性一半所需的配体浓度）为2.5μM。二价阳离子对反应至关重要，Mg2+、Ca2+和Mn2+的S0.5值分别为3.3mM、4mM和0.05mM。焦磷酸显著抑制该酶活性，I0.5值（达到最大抑制一半所需的配体浓度）为0.2mM，硫酸根的I0.5值为0.5mM，而磷酸根对酶活性的抑制作用较弱，I0.5约为20mM。通过在Sephadex G - 150柱上进行凝胶过滤，估计纯化酶的表观分子量为8×10(4)，并且该酶分子的斯托克斯半径约为0.36nm。蔗糖密度梯度离心显示该酶的沉降系数约为4.4S。
