News tagged with melanin

New research unlocks a mystery of albinism

Newly published research provides the first demonstration of how a genetic mutation associated with a common form of albinism leads to the lack of melanin pigments that characterizes the condition.

Dec 16, 2014
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Mutation V60L increases predisposition to skin cancer

When Homo sapiens left Africa and had to adapt to less sunny climates, there was a mutation in one of the genes responsible for regulating the synthesis of melanin, the MC1R gene, which involved a discoloration ...

Jan 14, 2014
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Is this peptide a key to happiness?

(Medical Xpress)—What makes us happy? Family? Money? Love? How about a peptide? The neurochemical changes underlying human emotions and social behavior are largely unknown. Now though, for the first time in humans, scientists ...

Mar 07, 2013
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Melanin

Melanin i/ˈmɛlənɪn/ (Greek: μέλας, black) is a pigment that is ubiquitous in nature, being found in most organisms (spiders are one of the few groups in which it has not been detected). In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms. All melanins can be considered as derivatives of polyacetylene, since they rely on a polyconiugate structure. Another common form of melanin is pheomelanin, a red-brown polymer of benzothiazine units largely responsible for red hair and freckles. The presence of melanin in the archaea and bacteria kingdoms is an issue of ongoing debate among researchers in the field.

The increased production of melanin in human skin is called melanogenesis. Production of melanin is stimulated by DNA damage induced by UVB-radiation, and it leads to a delayed development of a tan. This melanogenesis-based tan takes more time to develop, but it is long-lasting.

The photochemical properties of melanin make it an excellent photoprotectant. It absorbs harmful UV-radiation (ultraviolet) and transforms the energy into harmless heat through a process called "ultrafast internal conversion". This property enables melanin to dissipate more than 99.9% of the absorbed UV radiation as heat (see photoprotection). This prevents the indirect DNA damage that is responsible for the formation of malignant melanoma and other skin cancers.

This text uses material from Wikipedia licensed under CC BY-SA