Tyramine Tyrosine

Tropane alkaloids Turmerone Tyramine Tyrosine Umbelliferone Uric acid Ursolic acid Urushiol Valepotriates Valerianic acid Valeric acid Valtrate Vanillic acid... 

Gross AJ, Sizer IW. The oxidation of tyramine, tyrosine, and related compounds by peroxidase. J Biol Chem 1959 234 1622-1614. 

A variety of tritiated ( H) steroids are available as the radiolabeled compounds for use in the RIA. The relatively low sensitivity of H can be increased by multiple labeling. Another alternative is I labeling. Radioiodinated aromatic amines or amino acids, such as tyramine, tyrosine, or histamine, are linked to the steroid by the above-mentioned reactions to obtain the label. 

The decarboxylation of amino acids (name in brackets) leads to the biogenic amines phenyl-ethylamine (phenylalanine), tyramine (tyrosine), tryptamine (tryptophan), histamine (histidine), putrescine (ornithine) and cadaverine (lysine). The content of these compounds in some types of cheese is presented in Table 10.34. These values can fluctuate greatly depending on the degree of ripening. On average, 350-500 pmol per person per day are consumed. Apart from cheese. 

The bastadins are a series of predominantly macrocycUc bromotyrosine derivatives, which are biogeneticaUy derivable from four bromotyrosines by the oxidative phenohc coupling of two tyramine tyrosine units cormected through an amide bond. Until now, there are four acychc, twenty cychc bastadins, and sixteen hemibastadins isolated from marine sponges and ascidians. Examples of this class of alkaloids are bastadins-1 (204) and -5 (209). 

Trace Amines. Figure 1 The main routes of trace amine metabolism. The trace amines (3-phenylethylamine (PEA), p-tyramine (TYR), octopamine (OCT) and tryptamine (TRP), highlighted by white shading, are each generated from their respective precursor amino acids by decarboxylation. They are rapidly metabolized by monoamine oxidase (MAO) to the pharmacologically inactive carboxylic acids. To a limited extent trace amines are also A/-methylated to the corresponding secondary amines which are believed to be pharmacologically active. Abbreviations AADC, aromatic amino acid decarboxylase DBH, dopamine b-hydroxylase NMT, nonspecific A/-methyltransferase PNMT, phenylethanolamine A/-methyltransferase TH, tyrosine hydroxylase. 

Pyridoxamine phosphate serves as a coenzyme of transaminases, e.g., lysyl oxidase (collagen biosynthesis), serine hydroxymethyl transferase (Cl-metabolism), S-aminolevulinate synthase (porphyrin biosynthesis), glycogen phosphoiylase (mobilization of glycogen), aspartate aminotransferase (transamination), alanine aminotransferase (transamination), kynureninase (biosynthesis of niacin), glutamate decarboxylase (biosynthesis of GABA), tyrosine decarboxylase (biosynthesis of tyramine), serine dehydratase ((3-elimination), cystathionine 3-synthase (metabolism of methionine), and cystathionine y-lyase (y-elimination). 

In a related series of experiments, the amino group and/or the carboxylic acid group of tyrosine were replaced by hydrogen atoms. The corresponding tyrosine derivatives are 3-(4 -hydroxyphenyl)-propionic acid, commonly known as desaminotyrosine (Dat), and tyramine (Tym) (structures 3-5). 

Figure 13.7 Synthesis and structure of the trace amines phenylethylamine, /)-tyramine and tryptamine. These are all formed by decarboxylation rather than hydroxylation of the precursors of the established monoamine neurotransmitters, dopamine and 5-HT. (1) Decarboxylation by aromatic L-amino acid decarboxylase (2) phenylaline hydroxylase (3) tyrosine hydroxylase (4) tryptophan hydroxylase...

Tyramine is produced by decarboxylation of tyrosine and is present in the CNS in higher (threefold) concentrations than m-tyramine, the hydroxylated derivative of phenylethylamine. In the periphery / -tyramine is easily hydroxylated to octopamine, which has some direct effects on ai adrenoceptors, unlike tyramine which functions by releasing NA. When tested on central neurons tyramine always produces the same effects as NA but they are slower and less marked, implying an indirect action. By contrast octopamine often produces the opposite effect to NA and it is probable that octopamine may have a functional role in the invertebrate CNS where it is found in higher concentrations (5pg/g) than in the mammalian brain (0.5ng/g). Neither tyramine nor octopamine have distinct behavioural effects, unlike phenylethylamine,... 

Lequea et al. used the activity of tyrosine apodecarboxylase to determine the concentration of the enzyme cofactor pyridoxal 5 -phosphate (vitamin B6). The inactive apoenzyme is converted to the active enzyme by pyridoxal 5 -phosphate. By keeping the cofactor the limiting reagent in the reaction by adding excess apoenzyme and substrate, the enzyme activity is a direct measure of cofactor concentration. The enzymatic reaction was followed by detecting tyramine formation by LCEC. The authors used this method to determine vitamin B6 concentrations in plasma samples. 

Figure 4. Three naturally occurring tyrosine derivatives (desaminotyrosine, tyrosine, and tyramine) were used to prepare four different monomeric diphenols that carry no pendent chains (Dat-Tym), only a benzyloxycarbonyl (Z) group, only a hexyl ester group, or both types of pendent chains (Z-Tyr-Tyr-Hex).

Tyramine (4-hydroxy-phenethylamine, para-tyramine, / -tyramine) A phenolic amine CgHnNO, a monoamine compound derived from the amino acid tyrosine. 

C. Helene, T. Montenay-Garestier, and J. L. Dimicoli, Interactions of tyrosine and tyramine with nucleic acids and their components. Fluorescence, nuclear magnetic resonance, and circular dichroism studies, Biochim. Biophys. Acta 254, 349-365 (1971). 

Tyramine From Tyrosine. This is so easy that it is scary, and is probably the reason that tyrosine is watched very closely by the DBA. To avoid exposure to the DEA you may use the formula in the precursors section of this book. It is fairly simple to make. Also, your local health food store, Co-Op or livestock feed supplier may have tyrosine, as it is an important amino acid that is used sometimes as a feed supplement. These farm type suppliers that I have come to know do not report sales of tyrosine to the DEA. Maybe, in your part of the nation, they do. 

To decarboxilate tyrosine into tyramine, heat the tyrosine with barium hydroxide and separate, as seems practical (several ways are possible) to you. It will be easy to understand once you perform this operation, as it is really quite self-explanatory. Purify as described in JACS, 72, 2781 in the reductions chapter. 

Another strategy of some interest is to deplete biogenic amines such as OA by inhibiting their biosynthesis. Inhibitors of such enzymes in the biosynthetic pathway as aromatic amino acid decarboxylase which converts tyrosine to tyramine, or dopamine 3 -hydroxylase which converts tyramine to OA are known and have interesting effects in insects (e.g. see 52,53)t but a discussion of this area lies outside the scope of this paper. Nevertheless, it is a particularly interesting one since these or related enzymes are also needed to produce catecholamines for cuticular sclerotiza-tion, thus offering dual routes to the discovery of compounds with selectively deleterious actions on insects. 

Tyramine Tyramine, 4-(2-aminoethyl)phenol (11.2.1), can be synthesized in various ways, in particular by the decarboxylation of tyrosine [46-48]. It is also isolated from the tissues of livestock. 

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