from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A copper-containing enzyme of plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation, as in the blackening of a peeled or sliced potato exposed to air.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An enzyme, similar to catechol oxidase, that catalyzes the production of phenolic pigments such as melanin.
from The Century Dictionary and Cyclopedia
- n. An oxidizing ferment which acts upon tyrosin and leads to the formation of various black substances which are known only in part. The formation of homogentisic acid (alkapton) is probably referable to a tyrosinase. The black pigment secreted by the octopus is produced in this manner.
It actually helps block an enzyme called tyrosinase which is needed to make melanin.
Hydrogen peroxide attacks an enzyme called tyrosinase, which starts the production of melanin.
The gene alters the amino acid tyrosinase which is a necessary building block for the proteins that pigment hair and skin.
Not only that, but high levels of hydrogen peroxide and low levels of MSR A and B disrupt the formation of yet another enzyme, called tyrosinase, that leads to the production of hair pigments.
It includes tyrosinase activity (melanin is synthesed from tyrosine), DOPA production (used in threatment of Parkinson disease and depression) and in many other metabolytical pathways.
It works by blocking the enzyme tyrosinase inside the melanocytes that makes melanin.
The first step of the synthetic pathway for both eumelanins and pheomelanins is mediated by tyrosinase:
It was a surprise that the T cells of some melanoma patients recognized antigens in normal proteins -- a situation that verges on an auto-immune response; Boon's group has found two of these antigens in melanoma, Melan-A and tyrosinase.
It is an essential element, being part of enzymes like tyrosinase, cytochrome oxidase, etc.
People with a type of albinism - OCA1 - have light skin, white hair and light irises caused by defective tyrosinase genes which mean they struggle to produce melanin.
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