3,4-Dihydroxyphenylalanine-containing

W3. Waite, J. H., and Tanzer, M. L., Specific colorimetric detection of o-diphenols and 3,4-dihydroxyphenylalanine-containing peptides. Anal. Biochem. Ill, 131—136 (1981). 

Dihydroxyphenylalanine-containing proteins. Boronate affinity chromatography is used in the selective binding of proteins containing 3,4-dihydroxyphenylalanine to a m-phenylboronate agarose column and eluted with IM NH4OAC at pH 10. [Hankus et al. Anal Biochem 150 187 7956.]... 

Taylor, S.W., Luther 111, G.W., Waite, J.H. Polarographic and spectrophotometric investigation of iron (111) complexation to 3,4-dihydroxyphenylalanine-containing peptides and proteins from Mytilus edulis. Inorg. Chem. 33(25), 5819-5824 (1994)... 

Then, as described in U.S. Patent 3,158,648, the optical isomers may be resolved as follows. 37 g of racemic a-methYl-3,4-dihYdroxYphenylalanine are slurried at 35°C in 100 cc of 1.0 N hydrochloric acid. The excess solids are filtered leaving a saturated solution containing 34.6 g of racemic amino acid of which about 61% is present as the hydrochloride. The solution Is then seeded at 35°C with 7 g of hydrated L-o -methYl-3,4-dihYdroxYphenYlalanine (6.2 g of anhydrous material). The mixture is then cooled to 20°C in 30 minutes and aged one hour at 20°C. The separated material Is isolated by filtration, washed twice with 10 cc of cold water and dried in vacuo. The yield of product is 14.1 g of L-a-methYl-3,4-di-hydroxyphenylalanine in the form of a sesquihydrate of 100% purity as determined by the rotation of the copper complex. 

Allomelanins — These are structurally different compounds containing little or no nitrogen. They are considered polymers of phenolic compounds like catechol. Fnngi prodnce melanin pigments, predominantly dihydroxyphenylalanine (DOPA)-melanin and dihydroxynaphthalene (DHN)-melanin. ... 

Fio. 51. Dependence of retention of catecholamines on volume percent acetonitrile in hetaeric chromatography. The ehient is water-acetonitrile at the volume percent indicated containing 0.2% (v/v) sulfuric acid and 0.1% (w/v) sodium dodecyl sulfote. The catecholamines separated are noradrenaline (NA), adrenaline (A). L-3,4-dihydroxyphenylalanine (LD), normetanephrine (NMA), dopamine (DA), metadrenaline (MA), and 3-methoxytyramine (MDA). Column 5- tm octadecyl silica treated with triroethylchlorosilane, 125 X 5 mm i.d. Reprinted with permission from Knox and Jurand (223). ... 

The 216-residue hen egg yolk storage protein phosvitin contains 123 serine residues, most of which have been phosphorylated (Eq. 2-16).295 A basic protein of the myelin sheath of neurons contains as many as 6 specific residues of citrulline (Eq. 2-19).296 An adhesive protein from the foot of a marine mollusk contains -80 repeated sequences containing hydroxy-proline 2,3-dihydroxyproline and 3,4-dihydroxyphenylalanine (Dopa) 297/298... 

Tyrosine, itself a degradation product of phenylalanine (Sec. 15.1), is initially converted to 3.4-dihydroxyphenylalanine (dopa), and the corresponding do pa quinone, by the copper-containing enzyme tyrosinase. Tyrosinase is found in melanocytes and is a mixed-function oxidase. It catalyzes the following reaction ... 

Aromatic amino acids that originate from the shikimate pathway also act as precursors to many alkaloids. Alkaloids that contain a phenylethylamine moiety are derived from L-tyrosine or its oxidation product L-dihydroxyphenylalanine (L-DOPA). Mescaline (N7) originating from the latter amino acid is known to occur in several cacti and is responsible for the hallucinogenic activity of peyote (Lophophora williamsii, Cactaceae). Lophocerine is a tetrahydroisoquinoline alkaloid derived from L-dopamine and found to occur in a different Lophophora species, L. schotti. 

A further industrially important lyase for the production of L-amino acids is the tyrosine phenol lyase [39]. This biocatalyst is used by Ajinomoto in the production of the pharmaceutically important L-3,4-dihydroxyphenylalanine (L-dopa), 32, which is applied in the treatment of Parkinson s disease. The reaction concept is based on a one-pot three-component synthesis starting from catechol, 30, pyruvic acid, 31, and ammonia in the presence of suspended whole cells (strain Erwinia herbicola) containing the tyrosine phenol lyase biocatalyst (Fig. 16). A key feature of this process is the high volumetric productivity of 110 g/L of the desired L-dopa product. Notably, this reaction runs with an annual capacity of 250 tons. 

In this particular problem, a set of 27 samples containing different amounts of L-phenylalanine, L-3,4-dihydroxyphenylalanine (DOPA), 1,4-dihydroxybenzene and L-tryptophan have been measured by fluorescence spectroscopy [Baunsgaard 1999, Riu Bro 2002], The data are important as a model system for many biological systems, e.g. in food and environmental analysis. The goal here is to develop a PARAFAC model of the measured data because a PARAFAC model will ideally resolve the pure spectra as well as the relative concentrations of the analytes [Bro 1997, Bro 1998, Bro 1999, Leurgans et al. 1993, Leurgans Ross 1992, Ross Leurgans 1995]. 

A different approach to cyclodopa (alkyl 5,6-dihydroxy-2,3-dihydroindole-2-carboxylates has been devised (ref. 40) since the described process (ref.38) only results in acceptable yields when operated in very dilute solution. In the modified method. Scheme 5b, racemic 3,4-dihydroxyphenylalanine (dopa) methyl ester hydrochloride (C) was iodinated with potassium iodate in a two phase system, then treated with sodium dithionite and acetylated to afford methyl 5,6-diacetoxy-7-iodo-2,3-dihydroindole-2-carboxylate. Reductive treatment of this with Pd-C, and hydrogen in ethanolic solution containing triethylamine and conversion to the hydrochloride gave the product (methyl ester diacetate hydrochloride)in 40% overall yield. 

Fig. 4.4.12. Separation of a mixture of acidic and basic catecholamines on a LiChrosorb RP-8 column (0.28x25 cm). Eluent Water containing 0.02 M citrate (pH 2.5)/l% propanol/NaCIQ4 (0.08 M)/0.3% sodium dodecyl sulphate. Peaks DHMA, 3,4-dihydroxymandelic acid VMA, vanilmandelic acid HGA, 2,5-dihydroxyphenylacetic acid DOPAC, 3,4-dihydroxyphenylacetic acid 5-HIAA, 5-hydroxyindole-3-acetic acid HVA, homovanillylmandelic acid E, epinephrine NE, norepinephrine N-Syn, norsyneph-rine Syn, synephrine Dopa, 3,4-dihydroxyphenylalanine NM, normetanephrine MN, metanephrine Isopren, isoprenaline 3-H-Tyrm, dopamine Tyrm, tyramine 3-M-Tyrm, 3-methoxytyramine. Reprinted from Ref. 21 with permission.

The presently known cactus alkaloids are of simple chemical constitution. They are either substituted /3-phenethylamines, evidently related to and probably derived from the naturally occurring aromatic amino acids (tyrosine, dihydroxyphenylalanine, A -methyltyrosine, etc.), or they are simple tetrahydroisoquinolines that could originate from these bases by condensation and cyclization through the action of organic compounds containing one or two carbon atoms (formaldehyde and acetaldehyde equivalents ). 

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