melanin

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Related to Pheomelanin: Eumelanin

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 ?
A recent hypothesis claims that the consumption of a component of glutathione called cysteine, which occurs when pheomelanin is produced can be beneficial under conditions of low stress.
Some experiments on pheomelanin also have found antioxidant effects, while others indicate that it can promote oxidation.
The presentation, "Nonlinear High-Resolution Imaging of Eumelanin and Pheomelanin Distributions in Normal Skin Tissue and Melanoma" is at 8:45 a.
The team also suggest that pheomelanin synthesis could use up cells' antioxidant stores, meaning cells are more vulnerable to cancer.
On the other hand, the mutation of this gene also can suppress the activity of the MC1R gene, indirectly leading to more pheomelanin pigmentation (Guo et al.
The association may be stronger than a simple correlation, since the production of pheomelanin consumes GSH.
Sepia melanin was purchased from Sigma and used as a standard for spectrophotometric assay of total melanin, eumelanin and pheomelanin.
A cellular aspect of skin color is due to contributions by pheomelanin (red/yellow) and eumelanin (black/brown).
Both eumelanin and pheomelanin have the ability to generate active oxygen species, such as [O.
Whether canine follicular melanocytes synthesize red/yellow pheomelanin or black/brown eumelanin is determined by a small set of genes.
Melanins are responsible for the color of hair, as determined by the quantity of pheomelanin and eumelanin present in hair.
High performance liquid chromatography analysis of eu- and pheomelanin in melanogenesis control.