N- aspartic acid

Zaczek, R., Collins, J, and Coyle, J. T., 1981, JV-methyl-n-aspartic acid a potent convulsant with weak neurotoxic properties, Neurosci. Lett., 24 181-186. 

Ti-Aspartic Oxidase. Aspartase and transaminases account for a major part of the metabolism of L-aspartic acid. n-Aspartic acid is oxidized by an enzyme present in liver and kidney. This is an oxidase that converts aspartate to oxalacetate and ammonia while reducing oxygen to hydrogen peroxide. The oxidase was resolved by ammonium sulfate precipitation and dialysis to a protein that could be reactivated by FAD but not by FMN. The enzyme differs from n-amino acid oxidase in its insensitivity to benzoate. The only other known substrate for the partially purified D-aspartic oxidase is D-glutamate, but since the relative rates of oxidation of the two amino acids vary during the preparation of the enzyme, it is... 

D-Aspariic Acid Oxidase. Still et al. reported that rabbit kidney and liver contain a soluble enzyme which catalyzes the aerobic oxidation of D-aspartate to oxalacetate plus NH3 with the formation of hydrogen peroxide. In a later study by Still and Sperling the D-aspartic acid oxidase was resolved and reactivated by the addition of FAD. The purified enzyme showed about one-sixth the activity with D-glutamate this, according to these workers, is best explained by the presence of a D-glu-tamic acid oxidase. The activity of n-aspartic acid oxidase is higher than that of D-amino acid oxidase in rabbit kidney and liver, and they are of the same order of activity in pig kidney. In contrast to pig kidney o-amino acid oxidase, which is inhibited by benzoic acid, the D-aspartic acid oxidase was unaffected. 

A similar series of reactions with the corresponding hexenoic acid derivative was used for the demonstration that (-)-)norleucine is related to n(+)aspartic acid (Karrer and Itschner, 1936). The configuration of (-l-)a-aminophenylacetic acid, which behaves like an L-amino acid in physical and biological respects, has also been proved by chemical... 

Figure 6.3.5. (a) Basic schematic for a capillary electrophoresis system, (b) Capillary electrophoresis separation of dansyl amino acids A, unknown impurity B, c-labeled lysine C, dilabeled lysine D, asparagine E, isoleucine F, methionine G, serine H, alanine I, glycine J and K, unknown impurities L, dilabeled cysteine M, glutamic acid N, aspartic acid O, cysteic acid. The concentration of each derivative is approximately 5 x iO M, dissolved in operating buffer (Jorgenson and Lukacs, 1981). Beprinted, with permission, from Anal. Chem., 53, 1298, (1981), Figure 1, p. 1300. Copyri t (1981) American Chemical Society, (c) Effective velocities of cationic and anionic species in the presence of electroosmotic flow in a capillary. 

Alanine (ala) Phenylalanine (phe) R 1 0 - HNCHC N General formula for an amino acid residue Aspartic Acid (asp)... 

Fumaric acid occurs naturally in many plants and is named after Fumaria officinalis, a climbing aimual plant, from which it was first isolated. It is also known as (E)-2-butenedioic acid, aHomaleic acid, boletic acid, Hchenic acid, or /n j -l,2-ethylenedicarboxylic acid. It is used as a food acidulant and as a raw material in the manufacture of unsaturated polyester resins, quick-setting inks, furniture lacquers, paper sizing chemicals, and aspartic acid [56-84-8]. 

Fig. 10. Sequences (see Table 1) of betabeUins. In each case, only one-half of the P-sandwich is shown. The dimer is formed from identical monomeric sets of four P-strands. In the pattern sequence, e is for end, p is for polar residue, n is for nonpolar residue, and t and r are for turn residues. Lower case f is iodophenyialanine lower case a, d, k, and p are the D-amino acid forms of alanine, aspartic acid, lysine, and proline, respectively B is P-alanine (2,53,60,61).

In the case of thienamycin (Fig. lb) the absolute stereochemistry at C-5 was unambiguously deterrnined from the ene-lactam (16). The resultant (R)-aspartic acid (17) demonstrated that the absolute stereochemistry at C-5 of thienamycin is (R), corresponding to that found in the C-5 position of both penicillins and cephalosporins. Confirmation of the stereochemical assignments in both thienamycin (2) and the olivanic acid MM 13902 (3, n = 0) has been confirmed by x-ray crystallography (19,21,22). The stmctural determination of the nonsulfated derivatives from S. olivaceus (23), PS-5 (5) (5), the carpetimycins (6), and the asparenomycins (7) followed a similar pattern. 

N-Benzyloxycarbonyl-L-aspartic acid-a-p-nitrophenyl, /3-benzyl Diester Hydrogen... 

A solution of 88.5 parts of L-phenylalanine methyl ester hydrochloride in 100 parts of water is neutralized by the addition of dilute aqueous potassium bicarbonate, then is extracted with approximately 900 parts of ethyl acetate. The resulting organic solution is washed with water and dried over anhydrous magnesium sulfate. To that solution is then added 200 parts of N-benzyloxycarbonyl-L-aspartic acid-a-p-nitrophenyl, -benzyl diester, and that reaction mixture is kept at room temperature for about 24 hours, then at approximately 65°C for about 24 hours. The reaction mixture is cooled to room temperature, diluted with approximately 390 parts of cyclohexane, then cooled to approximately -18°C in order to complete crystallization. The resulting crystalline product is isolated by filtration and dried to afford -benzyl N-benzyloxycarbonvI-L-aspartyl-L-phenylalanine methyl ester, melting at about 118.5°-119.5°C. 

Labetalol HCI 4-Benzyloxyaniline HCI Hydroxytryptophan N-BenzyloxycarbonyI-L-aspartic acid-a-nitrophenyl,/3-benzyl diester Aspartame... 

The side-chain carboxylate group of an aspartic acid acts as a base and removes an acidic a proton from acetyl CoA, while the N-H group on the side chain of a histidine acts as an acid and donates a proton to the car bonyl oxygen, giving an enol. 

Merck s thienamycin synthesis commences with mono (V-silylation of dibenzyl aspartate (13, Scheme 2), the bis(benzyl) ester of aspartic acid (12). Thus, treatment of a cooled (0°C) solution of 13 in ether with trimethylsilyl chloride and triethylamine, followed by filtration to remove the triethylamine hydrochloride by-product, provides 11. When 11 is exposed to the action of one equivalent of tm-butylmagnesium chloride, the active hydrogen attached to nitrogen is removed, and the resultant anion spontaneously condenses with the electrophilic ester carbonyl four atoms away. After hydrolysis of the reaction mixture with 2 n HC1 saturated with ammonium chloride, enantiomerically pure azetidinone ester 10 is formed in 65-70% yield from 13. Although it is conceivable that... 

Grb-2 facilitates the transduction of an extracellular stimulus to an intracellular signaling pathway, (b) The adaptor protein PSD-95 associates through one of its three PDZ domains with the N-methyl-D-aspartic acid (NMDA) receptor. Another PDZ domain associates with a PDZ domain from neuronal nitric oxide synthase (nNOS). Through its interaction with PSD-95, nNOS is localized to the NMDA receptor. Stimulation by glutamate induces an influx of calcium, which activates nNOS, resulting in the production of nitric oxide. 

THE USE OF POLYSTYRYLSULFONYL CHLORIDE RESIN AS A SOLID SUPPORTED CONDENSATION REAGENT FOR THE FORMATION OF ESTERS SYNTHESIS OF N-[(9-FLUORENYLMETHOXY)CARBONYL]-L-ASPARTIC ACID a tert-BUTYL ESTER, P (2-ETHYL[(lE)-(4-NITROPHENYL)AZO] PHENYL]AMINO]ETHYL ESTER... 

To a 50-mL polypropylene vial (Note 1) are added 0.839 g (2.67 mmol) of 2-[ethyl[4-[(lE)-(4-nitrophenyl)azo]phenyl]amino]ethanol (Disperse Red 1, Note 2), 0.985 g of (2.39 mmol) N-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-aspartic acid,l-(l, 1-dimethylethyl) ester (Fmoc-L-Asp-OtBu, Note 3), 3.26 g (4.73 mmol) of polystyrylsulfonyl chloride resin (Note 4), and 30 mL anhydrous methylene chloride (Note 5). The vial is capped and the mixture is shaken for five min (Note 6). N-Methylimidazole (0.764 mL, 9.58 mmol) is then added to the deep red mixture (Note 7) and the resulting mixture is shaken for 2 hr (Note 8). 

N-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-aspartic acid, l-(l,l-dimethylethyl) ester L-Aspartic acid, N-[(9H-fluoren-9-ylmethoxy)carbonyl]-, l-(l,l-dimethylethyl ester (129460-09-9). 

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