EPR spectra of the investigated materials.

<div><p>DPPH (1,1-diphenyl-2-picrylhydrazyl) – marker for the position of the free radical signal (g=2.0037).</p> <p>(A) Dopa melanin and cysteinyl dopa melanin. (B) Hair of adult mouse (20 mg). (C) Melanin in skin (100 mg) of adult. (D). PND5 mouse skin. *- indicates the low field component of the splitting, used to calculate the a/b parameter (A). C57BL/6 and C57BL/6-HGF skin is compared to samples known for its content of pheomelanin, and often used as a pheomelanotic standard: hair of yellow C57BL/6-A^y/a and C57BL/6- Mc1r^e/e mice, and with amelanotic C57BL/6-<i>c</i>. Note that the pigment contained in the skin and in the hair is not pure pheomelanin, but a co-polymer with high contribution of pheomelanin. Also the used synthetic cysteinyldopa-melanin, besides semiquinonimine centres, contains semiquinones typical of eumelanins, with no interacting ¹⁴N.</p>