Alanine-0-sulfinic acid

A combination of D-amino acid oxidase and L-amino transferase is an example of a deracemization by stereoinversion. The product is an L-amino acid. The reaction catalyzed by amino transferase has an equilibrium constant close to unity, a very unpractical situation leading to uncomplete transformation and to the production of almost inseparable mixtures of amino acids (at least two, the amino acid product and the amino add used as an amino donor). For preparative purposes it is therefore mandatory to shift the equihbrium to the product side. A recent example of a deracemization procedure based on this coupled enzymatic system is the preparation of L-2-naphthyl-alanine 6 as illustrated in Scheme 13.9 [28]. The reaction occurs in one pot with initial oxidation of the D-amino acid catalyzed by D-amino acid oxidase from Rhodotonda gracilis. The hydrogen peroxide that is formed in stoichiometric amounts is decomposed by catalase. The a-keto add is the substrate for L-aspartate amino transferase (L-Asp amino transferase), which is able to use L-cysteine sulfinic acid 7 as an amino donor. 

As NJ eurotransmitters. Several amino acids serve as specialized neurotransmitters in both vertebrate and invertebrate nervous systems. These amino acids can be classified as inhibitory transmitters, such as y-aminobutyric acid [56-12-2] (GABA) and glycine, and excitatory amino acids, examples of which are L-glutamic acid and L-aspartic acid. A number of other amino acids and theic related substances occur in the brain and have some physiological activity. These include taurine [107-35-7], serine, profine, pipecofic acid [535-75-1], N-acetyl-aspartic acid [997-55-7], a- and p-alanines, and L-cysteine sulfinic acid [2381-08-0]. Eor more details about neurotransmitter amino acids, see reference 112. 

Fig. 2. The elution pattern of a standard mixture of OPA-derivatized primary amines, separated on a 5 (Jim Nucleosil C-18 column (200 X 4.6 mm id). The flow-rate was 1 mL/min employing the indicated gradient of metlianol and Na phosphate buffer (50 mA4, pH 5.25). Each peak represents 39 pmol except for those indicated below. 1, glutathione 2, cysteic acid 3, O-phosphoserine (19.5 pmol) 4, cysteine sulfinic acid 5, aspartic acid 6, asparagine (19.5 pmol) 7, glutamic acid 8, histidine 9, serine 10, glutamine 11, 3-methyl-histidine 12, a-aminoadipic acid (9.8 pmol) 13, citrulline (9.8 pmol) 14, carnosine 15, threonine,glycine 16, O-phosphoethanolamine 17, taurine (19.5 pmol) 18, p-alanine (19.5 pmol) 19, tyrosine 20, alanine 21, a-aminoisobutyric acid 22, aminoisobutyric acid 23, y-amino-ii-butyric acid 24, p-amino-u-butyric acid 25, a-amino-butyric acid 26, histamine 27, cystathione (19.5 pmol) 28, methionine 29, valine 30, phenylalanine 31, isoleucine 32, leucine 33, 5-hydroxytryptamine (5-H i ) 34, lysine. The chromatographic system consisted of a Varian LC 5000 chromatograph and a Schoeffel FS 970 fluorimeter.

L-Cysteine is transformed to L-cysteine sulfinic acid and L-cysteic acid. Cysteamine (D 11) yields hypotaurine and taurine (Fig. 189). The latter compounds may be transformed to other secondary products by deamination, thiolation, guanylation, and methylation. L-Cysteine sulfinic acid may be degraded to L-alanine and sulfurous acid, which is oxidized to sulfuric acid. 

For the preparation of 2-naphthyl alanine, a one-pot, two-step enzyme cascade was invented with d-AAO from Rhodotorula gracilis and an L-aminotransferase from E. coli [50]. Detail information about the deracemization steps was provided in Section 29.3.1 and shown in Scheme 29.3. Starting with the racemic 2-naphthyl alanine, the AAO generated the corresponding a-keto acid, which served as rfie substrate in the reductive amination step to enantiopure 2-naphthyl alanine. An irreversible amino donor, cysteine sulfinic acid, was used. 

S Additional information <9, 15, 17, 18, 21, 24, 30, 33, 35> (<18> activity is regulated by light [28] <30> D-aspartate, L-glutamate and -alanine are inactive as substitutes for L-aspartate in the forward reaction, in the reverse reaction ADP cannot be replaced by AMP, UDP, GDP or IDP [1] <17> aspartokinase III, o-isomers of the derivatives of aspartic acid, including D-aspartate cr-benzyl ester and o-aspartate /)-hydroxamate are not substrates regardless of whether the a- or the -carboxyl group is derivatized, L-cysteine sulfinate and 2-methyl-DL-aspartate are no substrates... 

Sodium N-(2-hydroxyethyl)-N-[2-[(1-oxododecyl) amino] ethyl]-p-alaninate. See Sodium lauroamphopropionate Sodium (Z)-N-[2-[(2-hydroxyethyl) (1-oxo-9-octadecenyl) amino] ethyl] glycinate. See Sodium oleoamphoacetate Sodium N-(2-hydroxyethyl)-N-[2-[(1 -oxooctadecyl) amino] ethyl] glycinate. See Sodium stearoamphoacetate Sodium 2-hydroxy-3-[(2-hydroxyethyl) [2-[(1-oxo-9-octadecenyl) amino] ethyl] amino] propanesulfonate. See Sodium oleoamphohydroxypropylsulfonate Sodium hydroxymethane sulfinate. See Sodium formaldehyde sulfoxylate Sodium hydroxymethane sulfonate CAS 870-72-4 EINECS/ELINCS 212-800-9 Synonyms Hydroxymethanesulfonic acid, monosodium salt Sodium formaldehyde bisulfite... 

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