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Dihydroxyphenyl: 3,4-dihydroxyphenylalanine

Sarac, S. Chankvetadze, B. Blaschke, G. Enantiosepara-tion of 3,4-dihydroxyphenylalanine and 2-hydrazino-2-methyl-3-(3,4-dihydroxyphenyl)propanoic acid by capillary electrophoresis using cyclodextrins. J. Chromatogr., A... [Pg.102]

The conversion of tyrosine to 3,4-dihydroxyphenylalanine occurs both in vivo in man (590) and in vitro by the action of tissue tyrosinase (205, 688). Mammals can decarboxylate both tyrosine (402,407) and dihydroxyphenyl-alanine (406), tyrosine decarboxylase and dihydroxyphenylalanine (dopa) decarboxylases being quite distinct and separable (405), though both are dependent on pyridoxal phosphate (73, 758, and review 72). In mammals dihydroxyphenylalanine is the most readily decarboxylated of all amino acids, and it is therefore not unreasonable to assume that this is the substrate normally decarboxylated in adrenaline biosynthesis cf. 74, 75). Support for this concept derives from the fact that both the substrate and the product of the reaction (3,4-dihydroxyphenylethylamine diagram 11) can or do occur in the adrenal (298, 299, 802), and the amine is moreover, like adrenaline and noradrenaline, a normal urinary excretion product (245, 404). [Pg.66]

In Scheme 13.40 and as noted above, the action of the iron-containing enzyme tyrosine 3-monooxygenase (EC 1.14.16.2) is shown to effect the conversion of tyrosine (Tyr, Y) and oxygen (O2) to 3,4-dihydroxyphenylalanine (L-dopa), while the cofactor tetrahydrobiopterin undergoes oxidation to 4a-hydroxytetrahydrobiop-terin. Then, the general aromatic-L-amino acid decarboxylase (EC 4.1.1.28), an enzyme that uses pyridoxal as a cofactor, effects the decarboxylation of the bisphe-noUc add to the corresponding amine, dopamine [3,4-dihydroxyphenethylamine, 2-(3,4-dihydroxyphenyl)ethanamine]. [Pg.1293]


See other pages where Dihydroxyphenyl: 3,4-dihydroxyphenylalanine is mentioned: [Pg.11]    [Pg.508]    [Pg.1634]    [Pg.395]    [Pg.510]    [Pg.367]    [Pg.85]    [Pg.536]   


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