Tyrosine L-DOPA

Some of the more interesting examples of nutrient - nonnutrient interactions include some of the compounds that are analogs of nutrients. Mattson et al (16) found that cholesterol absorption decreased when various plant sterols were added to the diets of rats. A number of plant amino acids are not ordinarily required by herbivores and are usually not incorporated into proteins. For example, the structure of 3,4-dihydroxyphenyl-alanlne (L-dopa) is similar to that of tyrosine. L-Dopa may play a role in favism (17), as well as having a number of other deleterious effects (18, 19, 20). Essential amino acids themselves can be deleterious if they are ingested in excessive quantities or if they are not in balance with other amino acids... 

Figure 29-3 Schematic diagram illustrating the dynamics of synthesis, exocytotic release (R), neuronal reuptake (NU), extraneurona uptake (EU), vesicular leakage (VL), vesicular sequestration (VS), and metabolism of norepinephrine (NE) in sympathetic nerve endings in relation to extraneuronal tissue and the bloodstream. Relative magnitudes of the various processes are reflected by the relative sizes of arrows. TH, Tyrosine hydroxylase MAO, monoamine oxidase COMT catechol-O-methyitransferase T R, tyrosine L-dopa, 3,4-dihydroxyphenyialanine DA, dopamine DHPG, 3,4-dihydroxyphenylglycol NMN, normetanephrine MHPG, 3-methoxy-4-hydroxypheny [glycol.

Based on its key regulating role, the melanocyte-specific enzyme tyrosinase has been evaluated by the measurement of its activity (abandoned due to poor sensitivity), substrates and/or metabolites (L-tyrosine, l-DOPA) and, more recently, by the detection and now... 

The preparation of the amino acid, alanine, in this way has enabled Langstrom and coworkers to prepare L-tyrosine, L-dopa, L-tryptophan and 5-hydroxy-L-tryptophan labelled in the carboxy group in good yields in less than one hour (equation 63). 

S)-Malate, Proteln(Glu-, Asp-), Peptide, RNA, ATP, deoxyATP, Pyruvate, Acetylcholine, Acetic ester, Dllsopropyl fluorophosphate, Stearoyl-CoA, Carbonate, Zinc, Copper, Manganese, Iron, L-Tyrosine, L-Dopa, 1,2-Benzenediol, Acetyl-CoA, beta-D-Galactoside, Thiogalactoside, Phenylgalactoside... 

Biosynthesis In the adrenal cortex from L-tyrosine -> L-DOPA — dopamine —> (/l)-noradrenaline - (R)-adrenaline. 

Compounds Derived from Phenylalanine and Tyrosine L-DOPA, Beta-... 

Daedaleopsis confragosa Russula nigricans Orange-red - grey -> black Tyrosine - L-DOPA(172) -Melanin (Scheme 31)... 

Molecular walght 197.19 (197.07) Synonyms 3-Hydroxy-l-tyrosine L-dopa... 

Phenol, L-tyrosine, l-DOPA Amperometry Pseudomonas putida Entrapment 0.1-1.0 pM phenol n.r. 160... 

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