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Related to Melanins: melanin deficiency
brown and black (eumelanins) or yellow (pheomelanins) water-insoluble macromolecular pigments.
Melanins, which are widespread in plants and animals, are responsible for the color of the integuments and their derivatives (hair, feathers, scales) in vertebrates, the cuticles in insects, and the rind in some fruits. In vertebrates, melanins are formed in special cells called melanocytes and deposited in the form of granules in which the melanins are bound to proteins (melano-proteins). The precursor of melanins in the body is the amino acid tyrosine, whose oxidation to dihydroxyphenylalanine (dopa) and subsequently to dopa quinone is catalyzed by the enzyme tyrosinase. Further transformations occur without the participation of enzymes and result in the formation of the melanins, whose chemical structures have not yet been established (empirical formula, C77H98O33N14S).
To a large extent, melanins determine the color of human skin, one of the main characteristics of race.
REFERENCESLerner, A. B. “Hormones and Skin Color.” Scientific American, 1961, vol. 205, no. 1.
Mason, H. S. “Structure of Melanins.” In Pigment Cell Biology. New York, 1959. Page 563.
Harley-Mason, J. “Melanins.” In Comprehensive Biochemistry, vol. 6. Amsterdam-London-New York, 1965.
E. V. BUDNITSKAIA