Sandbox Reserved 1097: Difference between revisions

First, TYRP1 has a role in [https://en.wikipedia.org/wiki/Melanin melanin] biosynthesis. Indeed, this enzyme has a catalytic function in the melanin biosynthetic pathway. In mouse, when a Cu2+ cation is bound, the protein catalyzes the oxidation of [https://pubchem.ncbi.nlm.nih.gov/compound/5_6-Dihydroxy-1H-indole-2-carboxylic-acid 5,6-dihydroxyindole-2-carboxylic acid (DHICA)] into [https://pubchem.ncbi.nlm.nih.gov/compound/Indole-5_6-quinone-2-carboxylate indole-5,6-quinone-2-carboxylic acid]. This protein is also able to catalyze the oxidation of [https://pubchem.ncbi.nlm.nih.gov/compound/5_6-Dihydroxyindole 5,6-dihydroxyindole (DHI)] into [https://pubchem.ncbi.nlm.nih.gov/compound/Indole-5_6-quinone indole-5,6-quinone]. Both products will allow to obtain eu-melanin, while pheo-melanin is obtain thanks to [https://www.uniprot.org/uniprot/P40126 TYRP2] activity <ref name= "koba"/>. The activity of the TYRP1 enzyme increase when the serine residues in position 505 and 509 are phosphorylated <ref name= "liu"/>. However, this mechanism does not happens in Humans because Human TYRP1 does not have the DHCIA activity. This can be explained by the fact that the nature of ions in the active site is different. Indeed, two Zn2+ ions bound the active site of the TYRP1 enzyme instead of two Cu2+, which are responsible for a different activity <ref name= "lai"/>. In fact, the incorporation of Cu2+ instead of Zn2+ in human TYRP1 active site, gives to the enzyme the DHICA activity, but no experiment has shown that Cu2+ can replace Zn2+ in vivo conditions.<ref name="Xlai"/> To conclude, the exact role of TYRP1 in pigmentation remains still unclear. Moreover, no gene polymorphism has been observed among caucasian population, despite the variation of hair and skin colors <ref name= "box"/>.