Vazquez E, Polo C, Batlle A M
Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP), (CONICET, UBA), Ciudad Universitaria, Buenos Aires, Argentine.
Cancer Biochem Biophys. 1995 Jun;15(1):55-63.
Rhodanese (thiosulfate: cyanide sulfurtransferase) shows distinctive mitochondrial and cytoplasmic activities in several models of tumorigenesis. To investigate the basis for these differences, the enzyme was purified from the mitochondrial and cytosolic liver fractions of mice treated with the carcinogen p-dimethyl-aminoazobenzene (DAB) and some properties were studied. Mitochondrial and cytoplasmic rhodanese exhibited different responses to the effect of ionic strength, denaturants, sulphydryl reagents, lipids and detergents, but no significant difference between enzymes purified from controls or DAB treated animals was observed. It is important to note that although chemical studies did not show very striking differences between either of the rhodanese forms, fluorescence spectral studies suggested that in DAB-treated mice, the cytosolic rhodanese would be present almost completely as the sulfur-free form, while the mitochondrial enzyme would be present as the sulfur-substituted form. These findings would justify the high rhodanese activity present in mitochondria. On the other hand, in control animals, rhodanese would exist only as the partial sulfur-substituted form in both fractions.
硫氰酸酶（硫代硫酸盐：氰化物硫转移酶）在几种肿瘤发生模型中表现出独特的线粒体和细胞质活性。为了探究这些差异的基础，从用致癌物对二甲氨基偶氮苯（DAB）处理的小鼠的线粒体和胞质肝部分中纯化该酶，并研究了一些特性。线粒体和细胞质硫氰酸酶对离子强度、变性剂、巯基试剂、脂质和去污剂的作用表现出不同的反应，但从对照或DAB处理动物中纯化的酶之间未观察到显著差异。需要注意的是，尽管化学研究未显示两种硫氰酸酶形式之间有非常显著的差异，但荧光光谱研究表明，在DAB处理的小鼠中，胞质硫氰酸酶几乎完全以无硫形式存在，而线粒体酶则以硫取代形式存在。这些发现可以解释线粒体中存在的高硫氰酸酶活性。另一方面，在对照动物中，硫氰酸酶在两个部分中仅以部分硫取代形式存在。
