Composition of Mammalian Eumelanins: Analyses of DHICA-Derived Units in Pigments From Hair and Melanoma Cells
| Autor: | Yutaka Mishima, Hirofumi Kondoh, Adam Wilczek |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Indoles
Polymers Clinical Biochemistry Melanoma Experimental Tumor cells Plant Science Biology White People Mice chemistry.chemical_compound Pigment Asian People Cricetinae Tumor Cells Cultured medicine Animals Humans Hair Color Melanins Melanoma DHICA Pigments Biological Cell Biology medicine.disease Mice Inbred C57BL chemistry Biochemistry Spectrophotometry visual_art visual_art.visual_art_medium Composition (visual arts) Agronomy and Crop Science Dopachrome tautomerase Hair Developmental Biology |
| Zdroj: | Pigment Cell Research. 9:63-67 |
| ISSN: | 1600-0749 0893-5785 |
| DOI: | 10.1111/j.1600-0749.1996.tb00090.x |
| Popis: | The proportions in which two eumelanin monomers, namely 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI), compose the eumelanin polymer are believed to determine properties of the pigment including its color. These proportions are, however, not well elucidated for naturally occurring eumelanins, largely because of methodological difficulties. In this study we estimate the content of DHICA-derived units in mammalian eumelanins using a combination of two analytical techniques: 1) quantitation of DHICA-derived eumelanin by measuring the yield of pyrrole-2,3,5-tricarboxylic acid (PTCA index) and 2) spectrophotometrical quantitation of total (DHI + DHICA) eumelanin at 350 nm (A350 index). The ratio of PTCA/A350 measured for melanins synthesized from DHI and DHICA mixed in various molar proportions correlates well with the content of DHICA in synthetic polymers. Using this relationship as a standard curve we estimated the proportion of DHICA-derived units in mammalian eumelanins from hair and melanoma cells and found it to be much higher in rodent pigments (58.8%-98.3%; two species, mouse and hamster were examined) as compared to human eumelanins (19.2%-41.8%; one Caucasian and one Oriental individual were examined). No relationship between proportion of DHICA-derived units in eumelanin and hair color is found. The latter seems to be determined predominantly by the ratio of pheo- to eumelanin synthesis. |
| Databáze: | OpenAIRE |
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