Abstract: A novel catalytic property of hemin is described. In ammonium buffer medium of pH 8.0～8.9, hemin has an ability to catalyze the decoloration of bromopyro-gallol red. Oxygen dissolved in solution plays a role as an oxidant in the reaction. With sodium dodecylbenzenesulfonate and ethanol as effect-enhancing agents, the catalytic system obeys the Michaelis-Menten equation of enzymatic catalysis. The Michaelis constant, catalytic constant and specificity constant of the system are estimated by Lineweaver-Burk plot to be 3.7×10^-5mol/L, 0.64s^-1 and 1.7×10⁴L·mol^-1·s^-1, respectively. The mechanism of the hemin oxidase-like catalytic system is discussed. Based on this, hemin can be spectrophotometrically determined by equilibrium and kinetic procedures with a linear range and 3σ limit of detection being 2.0×10^-8～6.0×10^-7 and 5.0×10^-9mol/L, respectively.

Key words: Hemin, Mimetic enzyme, sodium dodecylbenzenesulfonate, bromopyro-gallol red

摘要： 研究了十二烷基苯磺酸钠(SDBS)存在下氯化血红素(Hemin)类似过氧化物酶的新型催化活性。在pH 8.0～8.9氨性缓冲介质中，Hemin催化溶解氧氧化溴邻苯三酚红的褪色反应。在SDBS和30%乙醇的增效作用下，催化体系服从Michaelis-Menten方程。用Lineweaver-Burk作图法求得米氏常数、催化常数和专一性常数分别为3.7×10^-5mol/L, 0.64s^-1和1.7×10⁴L·mol^-1·s^-1。对机理进行了讨论。利用该催化体系，用反应平衡法和动力学法均可分光光度定量Hemin, 线性范围为2.0×10^-8～6.0×10^-7mol/L，检测限为2.5×10^-9mol/L。

关键词: 氯化血红素, 模拟酶, 十二烷基苯磺酸钠, 溴连苯三酚红