Carstam R, Edner C, Hansson C, Lindbladh C, Rorsman H, Rosengren E
Acta Derm Venereol Suppl (Stockh). 1986;126:1-12.
5-S-Glutathionyldopa is oxidized at incubation with tyrosinase and dopa producing a black pigment. The reaction proceeds with the formation of two chromophores with absorption spectra similar to those of dopachrome and melanochrome, respectively. Zn2+ catalyses the formation of the melanochrome-like compound. The oxidation of 5-S-glutathionyldopa by dopaquinone, formed by the action of human tyrosinase and mushroom tyrosinase, is considerably slower than that of 5-S-cysteinyldopa. The higher oxidation potential of 5-S-glutathionyldopa, and/or the greater number of dopaquinone molecules necessary for pigment formation from 5-S-glutathionyldopa and/or the formation of tyrosinase-inhibiting products from 5-S-glutathionyldopa can explain the slower oxidation of this compound. The oxidative pathways suggested for 5-S-glutathionyldopa by the present findings may be relevant both in the melanocyte and in non-specific oxidation of cathechols occurring in other cells.
5-S-谷胱甘肽多巴在与酪氨酸酶和多巴一起孵育时被氧化，生成一种黑色色素。该反应进行时会形成两种发色团，其吸收光谱分别与多巴色素和黑素铬的吸收光谱相似。锌离子催化类黑素铬化合物的形成。由人酪氨酸酶和蘑菇酪氨酸酶作用形成的多巴醌对5-S-谷胱甘肽多巴的氧化作用，比5-S-半胱氨酰多巴的氧化作用要慢得多。5-S-谷胱甘肽多巴较高的氧化电位，和/或从5-S-谷胱甘肽多巴形成色素所需的多巴醌分子数量较多，和/或从5-S-谷胱甘肽多巴形成酪氨酸酶抑制产物，可以解释该化合物氧化较慢的原因。本研究结果所提出的5-S-谷胱甘肽多巴的氧化途径，可能在黑素细胞以及其他细胞中发生的儿茶酚非特异性氧化过程中都具有相关性。
