Rachkova M, Raikova E, Raikov Z
Department of Chemistry and Biochemistry, Medical Institute, Stara Zagora, Bulgaria.
Cancer Biochem Biophys. 1991 Jun;12(1):59-64.
Tyrosinase is a key enzyme in melanine biosynthesis. The modulating effect of cytostatic agents on DOPA-oxidase activity of tyrosinase could be linked with the drug treatment of melanoma tumors. Two groups of nitrosoureas which influence DOPA-oxidase activity of tyrosinase were studied: new nitrosoureas and their spin-labeled derivatives synthesized in our laboratory. Using Burnett's spectrophotometric method (Burnett et al., 1967) the following effects were established: inhibition by CCNU, inhibition and the activating effects of the other investigated nitrosoureas depend on their physicochemical half-life. The predominant activating effect of the spin-labeled derivatives is due to the nitroxyl radical present in these compounds.
酪氨酸酶是黑色素生物合成中的关键酶。细胞抑制剂对酪氨酸酶多巴氧化酶活性的调节作用可能与黑色素瘤肿瘤的药物治疗有关。研究了两组影响酪氨酸酶多巴氧化酶活性的亚硝基脲：我们实验室合成的新型亚硝基脲及其自旋标记衍生物。采用伯内特分光光度法（伯内特等人，1967年）确定了以下效应：CCNU的抑制作用，其他研究的亚硝基脲的抑制和激活作用取决于它们的物理化学半衰期。自旋标记衍生物的主要激活作用归因于这些化合物中存在的硝酰基自由基。
