Menon I A, Persad S D, Haberman H F, Basu P K, Norfray J F, Felix C C, Kalyanaraman B
Department of Medicine, University of Toronto, Ont., Canada.
Biochem Cell Biol. 1991 Apr;69(4):269-73. doi: 10.1139/o91-041.
When urine samples from alkaptonuria patients are allowed to stand, they turn black, presumably owing to the oxidation of homogentisic acid to a melanin-like substance. We report the characterization of the pigments formed by polymerization of (a) the components in the urine from a patient with alkaptonuria and (b) homogentisic acid. The absorption spectra and electron spin resonance signals of these pigments are similar to those of eumelanins. Irradiation of the pigments with nitroblue tetrazolium caused reduction of the tetrazolium; this was partially inhibited by superoxide dismutase. Irradiation of Ehrlich ascites carcinoma cells with the pigments from homogentisic acid or urine caused cell lysis. Since this lysis was inhibited by catalase, we have concluded that it was mediated by H2O2. A similar pigment was also extracted from the tissue from an alkaptonuria patient. It is suggested that the degeneration of tissue in vivo may be due to the deposition of melanin-like pigments in the tissues, probably in combination with metal ions.
当将黑尿症患者的尿液样本静置时，它们会变黑，推测这是由于尿黑酸氧化成一种类似黑色素的物质所致。我们报告了由（a）一名黑尿症患者尿液中的成分和（b）尿黑酸聚合形成的色素的特性。这些色素的吸收光谱和电子自旋共振信号与真黑素的相似。用硝基蓝四氮唑照射这些色素会导致四氮唑还原；超氧化物歧化酶可部分抑制这种还原。用尿黑酸或尿液中的色素照射艾氏腹水癌细胞会导致细胞裂解。由于这种裂解被过氧化氢酶抑制，我们得出结论，它是由过氧化氢介导的。还从一名黑尿症患者的组织中提取出了类似的色素。有人提出，体内组织的退化可能是由于类似黑色素的色素在组织中沉积所致，可能还与金属离子有关。
