脱氧胞苷酸脱氨酶。来自幼仓鼠培养肾细胞的该酶的性质。
Deoxycytidylate deaminase. Properties of the enzyme from cultured kidney cells of baby hamster.
作者信息
Rolton H A, Keir H M
出版信息
Biochem J. 1974 Jul;141(1):211-7. doi: 10.1042/bj1410211.
dCMP deaminase was partially purified from BHK-21/C13 cells grown in culture. The molecular weight of the enzyme was estimated by gel filtration and gradient centrifugation to be 130000 and 115000 respectively. The enzyme had a pH optimum of 8.4. Its activity versus substrate concentration curve was sigmoid, the substrate concentration at half-maximal velocity being 4.4mm. dCTP activated the deaminase maximally at 40mum, gave a hyperbolic curve for activity versus dCMP concentration and a K(m) value for dCMP of 0.91mm. dCTP activation required the presence of Mg(2+) or Mn(2+) ions. dTTP inhibited the deaminase maximally at 15mum; the inhibition required the presence of Mg(2+) or Mn(2+) ions. The enzyme was very heat-labile but could be markedly stabilized by dCTP at 0.125mm and ethylene glycol at 20% (v/v).
从培养的BHK - 21/C13细胞中部分纯化了dCMP脱氨酶。通过凝胶过滤和梯度离心法估计该酶的分子量分别为130000和115000。该酶的最适pH为8.4。其活性与底物浓度曲线呈S形，最大反应速度一半时的底物浓度为4.4mmol/L。dCTP在40μmol/L时对脱氨酶的激活作用最大，其活性与dCMP浓度曲线呈双曲线，dCMP的米氏常数（K(m)）值为0.91mmol/L。dCTP激活需要Mg(2+)或Mn(2+)离子的存在。dTTP在15μmol/L时对脱氨酶的抑制作用最大；这种抑制作用需要Mg(2+)或Mn(2+)离子的存在。该酶对热非常不稳定，但在0.125mmol/L的dCTP和20%（v/v）的乙二醇存在下可显著稳定。
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