Melanin Open Access Articles

 Melanin is widely dispersed within the animal and plant kingdoms. It is the main pigment present within the surface structures of vertebrates. The critical step in melanin biogenesis is that the oxidation of tyrosine by the enzyme tyrosinase. In vertebrates this enzyme is active only in specialized organelles in retinal pigment epithelium and melanocytes. In mammals melanin is formed as intracellular granules. Melanin has many biological functions. Reactive quinone intermediates within the melanin biosynthetic pathway exhibit antibiotic properties and therefore the polymer is a crucial strengthening element of plant cell walls and bug cuticle. Light absorption by melanin has several biological functions, including photoreceptor shielding, thermoregulation, photoprotection, camouflage and display. Melanin may be a powerful cation chelator and should act as a radical sink. Melanin is employed commercially as a component of photoprotective creams, although mainly for its radical scavenging instead of its light absorption properties. The pigment is additionally a possible target for anti-melanoma therapy. Melanins are a category of darkly pigmented biopolymers which are cosmopolitan among living organisms. THere, a pair of barley near isogenic lines, bred to differ with reference to the pigmentation of the spike, was compared so as to know the tissue and cellular location of melanin deposition. The melanic nature of the pigments purified from black spikes was confirmed by a series of solubility tests and Fourier transform infrared spectroscopy.