CHEMICAL CHARACTERIZATION OF HAIR MELANINS IN VARIOUS COAT-COLOR MUTANTS OF MICE

Mammalian melanins exist in two chemically distinct forms: the brown t o black eumelanins and the yellow to reddish pheomelanins. Melanogenes is is influenced by a number of genes, the levels of whose products de termine the quantity and quality of the melanins produced, To examine the effects of various coat-color genes on the chemical properties of melanins synthesized in the follicular melanocytes of mice, we have in troduced new methods to solubilize differentially pheomelanins and bro wn-type eumelanins, We applied these and previously developed high-per formance liquid chromatography and spectrophotometric methods for assa ying eu- and pheomelanins to characterize melanins in various mutant m ice: black, lethal yellow, viable yellow, agouti, brown, light, albino , dilute, recessive yellow, pink-eyed dilution, slaty, and silver, It was demonstrated that 1) complete solubilization of melanins in Soluen e-350 is a convenient method to estimate the total amount of eu- and p heomelanins, 2) lethal yellow, viable yellow, and recessive yellow hai rs contain almost pure pheomelanins, and 3) melanins from brown, light , silver, and pink-eyed black hairs share chemical properties in commo n that are characterized by partial solubility in strong alkali, We su ggest that 1) the brown-type eumelanins have lower degrees of polymeri zation than the black-type eumelanins, and 2) slaty hair melanin conta ins a greatly reduced ratio of 5,6-dihydroxyindole-2-carboxylic acid-d erived units as compared with black and other eumelanic hair melanins, These results indicate that our methodology, high-performance liquid chromatography and spectrophotometric methods combined, may be useful in chemically characterizing melanin pigments produced in follicular m elanocytes.