Editing Mescaline (section)

===Biosynthesis===
[[File:Mescaline biosynthetic pathways.svg|class=skin-invert-image|thumb|right|400px|[[Biosynthesis]] of mescaline.]]

Mescaline is [[biosynthesis|biosynthesized]] from [[tyrosine]], which, in turn, is derived from [[phenylalanine]] by the enzyme phenylalanine hydroxylase. In ''Lophophora williamsii'' ([[Peyote]]), [[dopamine]] converts into mescaline in a biosynthetic pathway involving ''m''-''O''-methylation and aromatic hydroxylation.<ref>{{Cite book |title=Medicinal Natural Products: A Biosynthetic Approach | vauthors = Dewick PM |location=United Kingdom |publisher=John Wiley & Sons |pages=335–336 |year=2009 |isbn=978-0-471-49641-0 }}</ref>

Tyrosine and phenylalanine serve as metabolic precursors towards the synthesis of mescaline. Tyrosine can either undergo a decarboxylation via [[tyrosine decarboxylase]] to generate [[tyramine]] and subsequently undergo an oxidation at carbon 3 by a [[monophenol hydroxylase]] or first be hydroxylated by [[tyrosine hydroxylase]] to form [[L-DOPA]] and decarboxylated by [[DOPA decarboxylase]]. These create dopamine, which then experiences methylation by a [[catechol-O-methyltransferase]] (COMT) by an [[S-Adenosyl methionine|''S''-adenosyl methionine]] (SAM)-dependent mechanism. The resulting intermediate is then oxidized again by a hydroxylase enzyme, likely monophenol hydroxylase again, at carbon 5, and methylated by COMT. The product, methylated at the two meta positions with respect to the alkyl substituent, experiences a final methylation at the 4 carbon by a guaiacol-O-methyltransferase, which also operates by a SAM-dependent mechanism. This final methylation step results in the production of mescaline.

Phenylalanine serves as a precursor by first being converted to <small>L</small>-tyrosine by [[L-amino acid hydroxylase]]. Once converted, it follows the same pathway as described above.<ref name="10.1016/j.plantsci.2006.10.013">{{cite journal |vauthors=Kulma A, Szopa J |date=March 2007 |title=Catecholamies are active compounds in plants |journal=Plant Science |volume=172 |issue=3 |pages=433–440 |doi=10.1016/j.plantsci.2006.10.013|bibcode=2007PlnSc.172..433K }}</ref><ref>{{cite journal | vauthors = Rosengarten H, Friedhoff AJ | title = A review of recent studies of the biosynthesis and excretion of hallucinogens formed by methylation of neurotransmitters or related substances | journal = Schizophrenia Bulletin | volume = 2 | issue = 1 | pages = 90–105 | year = 1976 | pmid = 779022 | doi = 10.1093/schbul/2.1.90 | doi-access =}}</ref>