Dictionary > Melanogenesis

Melanogenesis

Definition
noun
The process of producing melanin
Supplement
Melanogenesis is the process of melanin production. Melanocytes are cells that produce and store melanin, particularly at the melanosome (organelle). Melanin refers to a group of pigments produced from the oxidation of tyrosine, followed by polymerization. It is the one responsible for the color of skin, feathers, hair, fur, eyes, scales, etc. There are three basic types of melanin: (1) eumelanin, (2) pheomelanin, and (3) neuromelanin.
The eumelanin is the most common type among the three. The eumelanin may be brown or black in colour. Eumelanin polymer is made up of cross-linked 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) polymers. Eumelanin is produced through a series of catalysed chemical reactions, starting from tyrosine, and with tyrosinase as the key enzyme.
The pheomelanin is a pigment made up of benzothiazine units that is largely responsible for the red pigmentation. Similar to eumelanin, the biosynthesis pathway of pheomelanin begins at tyrosine. It proceeds to the route with an end result of alanyl-hydroxy-benzothiazine in the presence of gluthathione or cysteine.
The neuromelanin is a dark pigment comprised of 5,6-dihydroxyindole monomers. It is made up of a polymer of 5,6-dihydroxyindole monomers. Similar to eumelanin, it is synthesized directly from L-DOPA through the catalytic activity of tyrosine hydroxylase and aromatic acid decarboxylase.
See also:


You will also like...

"Cronopio dentiacutus", a prehistoric mammal (an illustration)
Mammalian Ancestors

Mammals are a diverse group of organisms, where most of them develop their offspring within the uterus of the mother. Ov..

Human Reproduction
Human Reproduction

Humans are capable of only one mode of reproduction, i.e. sexual reproduction. Haploid sex cells (gametes) are produced ..

Sugar Homeostasis
Sugar Homeostasis

The blood sugar level is regulated by two hormones. The mechanism behind this type of negative feedback control is descr..

primitive arthropods
Arthropods

The arthropods were assumed to be the first taxon of species to possess jointed limbs and exoskeleton, exhibit more adva..

Early Earth
The Origins of Life

This tutorial digs into the past to investigate the origins of life. The section is split into geological periods in the..

Lake Wakatipu, New Zealand
New Zealand’s Unique Geographical History

Explore why New Zealand has such unique flora and fauna, and learn why long periods of geographical isolation. This less..

Related Articles...

No related articles found

See all Related Topics