melanin


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melanin

(mĕl`ənĭn), water-insoluble polymer of various compounds derived from the amino acid tyrosinetyrosine
, organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein.
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. It is one of two pigments found in human skin and hair and adds brown to skin color; the other pigment is carotenecarotene
, long-chained, unsaturated hydrocarbon found as a pigment in many higher plants, particularly carrots, sweet potatoes, and leafy vegetables. Carotene is thought to assist in trapping light energy for photosynthesis or to aid in chemical reduction.
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, which contributes yellow coloring. The synthesis of melanin reactions is catalyzed by the enzyme tyrosinase; an inherited lack of tyrosinase activity results in one of the forms of albinism. Tyrosinase is found in only one specialized type of cell, the melanocyte, and in this cell melanin is found in membrane-bound bodies called melanosomes. Melanosomes can be transferred from their site of synthesis in the melanocytes to other cell types. The various hues and degrees of pigmentation found in the skin of human beings are directly related to the number, size, and distribution of melanosomes within the melanocytes and other cells. Besides it role in pigmentation, melanin, which absorbs ultraviolet light, plays a protective role when skin is exposed to the damaging rays of the sun (see sunburnsunburn,
inflammation of the skin caused by actinic rays from the sun or artificial sources. Moderate exposure to ultraviolet radiation is followed by a red blush, but severe exposure may result in blisters, pain, and constitutional symptoms.
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; skin cancerskin cancer,
malignant tumor of the skin. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Rarer forms include mycosis fungoides (a type of lymphoma) and Kaposi's sarcoma.
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).

melanin

[′mel·ə·nən]
(biochemistry)
Any of a group of brown or black pigments occurring in plants and animals.

melanin

any of a group of black or dark brown pigments present in the hair, skin, and eyes of man and animals: produced in excess in certain skin diseases and in melanomas
References in periodicals archive ?
It s certainly more important than melanin in lightly-pigmented skin, he said.
delta]T3 has been found to decrease melanin levels in mouse B16 melanoma cells by inhibiting the oxidative reactions of tyrosinase (Michihara et al.
Gerec ve Yontemler: Diseti melanin pigmentasyonundan rahatsiz olan ve bunun giderilmesini isteyen 21 hasta calismaya alindi.
As previously mentioned, ultraviolet rays encourage the production of melanin as a protective measure.
French company Avene has a product called D-Pigment, which contains a skin lightening derivative of Vitamin A and ingredients to slow down the production of melanin.
Our study shows that we were able to discover this new role for melanin by cleanly separating UVA from UVB and exposing our experimental melanoma animal model with these separated wavebands using our unique UV light system designed and set up at GW.
Excessive sun exposure and skin injuries or irritation are common causes of “overactive melanin.
As we age, our body may stop producing melanin, causing the hair to grow in gray or white," says Dr.
The amount of melanin produced by these cellular fabrics is dependent on individual predisposition and stimulation by sunlight, thereby providing a natural protection of the skin against UV irradiation and sunburn.
A lot of study has been done in this area by European institutes, including the universities of Bradford, Manchester and Mainz (Germany), which have determined that melanin is present both before and after the onset of grey hair.
s Mel-Lumen CFL with melanin is a replacement for traditional CFLs.