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Usefulness of alkaline hydrogen peroxide oxidation to analyze eumelanin and pheomelanin in various tissue samples: application to chemical analysis of human hair melanins
Author(s) -
Ito Shosuke,
Nakanishi Yukiko,
Valenzuela Robert K.,
Brilliant Murray H.,
Kolbe Ludger,
Wakamatsu Kazumasa
Publication year - 2011
Publication title -
pigment cell and melanoma research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.618
H-Index - 105
eISSN - 1755-148X
pISSN - 1755-1471
DOI - 10.1111/j.1755-148x.2011.00864.x
Subject(s) - chemistry , hydrogen peroxide , permanganate , alkaline hydrolysis , pyrrole , tricarboxylic acid , biochemistry , chromatography , hydrolysis , organic chemistry , citric acid cycle , enzyme
Summary Eumelanin and pheomelanin in tissue samples can be specifically measured as the markers pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and 4‐amino‐3‐hydroxyphenylalanine after acidic permanganate oxidation and hydroiodic acid hydrolysis, respectively. Those degradation methods, although widely applied, are not easily performed in most laboratories. To overcome this difficulty, we developed alkaline H 2 O 2 oxidation in 1 M K 2 CO 3 that produces, in addition to the eumelanin marker PTCA, thiazole‐2,4,5‐tricarboxylic acid (TTCA) and thiazole‐4,5‐dicarboxylic acid (TDCA) as markers for pheomelanin and pyrrole‐2,3‐dicarboxylic acid (PDCA) as a marker for 5,6‐dihydroxyindole‐derived eumelanin. Those four degradation products can be easily separated by HPLC and analyzed with ultraviolet detection. The alkaline H 2 O 2 oxidation method is simple, reproducible and applicable to all pigmented tissues. Its application to characterize eumelanin and pheomelanin in human hair shows that PTCA and TTCA serve as specific markers for eumelanin and pheomelanin, respectively, although some caution is needed regarding the artificial production of TTCA from eumelanic tissue proteins.