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Acetylamino acid

T.-amino acids DL-acetylamino acids L- amino acylase A.sp. oryc e 25... [Pg.292]

Archer, owing to very unfortunate coincidences, had mistaken acid potassium tartrate for the acetylamino acid. Goldfarb et al. prepared authentic 5-acetylamino-2-thiophenecarboxylic acid, mp 230 232°C (methyl ester, mp 171-171.5°C ethyl ester, mp 161°C), through reduction of 5-nitro-2-thiophenecarboxylic acid with Raney nickel in acetic anhydride and proved the structure by Raney nickel desulfurization to 8-aminovaleric acid. They also confirmed that the acid mp 272-273°C (methyl ester, mp 135-136°C ethyl ester, mp 116-117°C) is 4-acetylamino-2-thiophenecar boxy lie acid as originally stated by Steinkopf and Miiller. The statement of Tirouflet and Chane that the acid obtained upon reduction and acetylation of 5-nitro-2-thiophenecarboxylic acid melts at 272°C must result from some mistake as they give the correct melting point for the methyl ester. [Pg.51]

Treatment of the carbanion derived from 94 with nitriles was shown to give enaminesulfoxides 136, which can be converted to a-ketoesters or a-ketoacylamides185, besides the ester of JV-acetylamino acid 137. Using this reaction, the methyl ester of dl-JV-acetyl-5-hydroxytryprophane 138 was synthesized186. [Pg.615]

The BDPCH system was again effective for the a-acetamido olefinic acids (up to 79% ee, which could be increased to nearly 100% ee after recrystallization of the A-acetylamino acid products), while the BDPCP system gave 60% ee for hydrogenation of a-ethylstyrene which is one of the highest ee values yet recorded for a substrate containing no polar substituents (—COOH, CONHR) (see also Section IV,B). [Pg.349]

These observations are common to the series of N-acetylamino acids which have been investigated. Whereas the carbon monoxide to carbon dioxide yield for the aliphatic carboxylic acids are in the approximate ratio of 1 10, the corresponding ratio for the N-acetyl amino acids is much smaller, because of the much smaller yields for carbon monoxide. This suggests that there must be another site on which the ejected electron can be trapped with greater efficiency than that for trapping on the carboxyl group. [Pg.86]

Fig. 9 Correlation of (A) the second order rate constants (k2 = kcatIKM) and (B) the transition stabilization (pATS) with the hydrophobicity (it) of the substituent of the amino acid residue for the cleavage of /V-acetylamino acid methyl esters by a-chymotrypsin. The open symbols are for the points for two branched residues (valine and isoleucine). Data from Table A6.8. Fig. 9 Correlation of (A) the second order rate constants (k2 = kcatIKM) and (B) the transition stabilization (pATS) with the hydrophobicity (it) of the substituent of the amino acid residue for the cleavage of /V-acetylamino acid methyl esters by a-chymotrypsin. The open symbols are for the points for two branched residues (valine and isoleucine). Data from Table A6.8.
Table A6.8 Cleavage of /V-acetylamino acid methyl esters by a-chymotrypsin."... Table A6.8 Cleavage of /V-acetylamino acid methyl esters by a-chymotrypsin."...
In addition, detailed geometric and energetic characteristics of the elementary reaction pathways for the addition of water and ammonia to 2-methyl-5(477)-oxazolone have been determined at the AMI level using MOPAC programs. The authors concluded that an A-acetylamino acid or amide are formed through a two-step procedure that involves the formation of the a-hydroxyimine and subsequent tautomerization. [Pg.179]

Tlie amino group of the racemic amino acid is acetylated with acetic anhydride to give racemic N-acetylamino acid. The deacylase hydrolyzes only the i. enantiomer, which is thereby separated from the d enantiomer. The latter is then chemically hydrolyzed to give the free d amino acid. [Pg.492]

Lack of congruence of sequence and structure with function Common sequence and structure, indeed identity of the protein itself, do not imply a unique function Each pair, o-succinylbenzoate synthase (OSBS)-N-acetylamino acid racemase, and lens crystallin-lactate dehydrogenase, share sequence and structure but differ in function. [Pg.460]

Enolases mandelate racemase (MR), muconate-lactonizing enzyme (MLE), N-acetylamino acid racemase (NAAR) Hasson, 1998 Palmer, 1999... [Pg.464]

NAAR N-acetylamino acid racemase OSBS O-succinylbenzoate synthase. [Pg.470]

N -Acetylamino acid hydrolase N -Acetyl amino acids Amino acids 36, 37... [Pg.2125]

H-labeled model compounds prepared from the inactivator and N-acetylamino acids showed that only histidine and cysteine were labeled in the protein. [Pg.231]

Mercuric salts of carboxylic acids decompose in uv light or in the presence of peroxides to form alkylmercury derivatives. Aqueous peroxydisulfate can be used to decarboxylate N-acetylamino acids to give aldehydes or ketones, acetamide, and CO2. ... [Pg.324]

ESR evidence for this electron adduct of the carbonyl group in frozen solutions of acetylamino acids and di- and tripeptides is extensive (50). A typical spectrum is shown in Figure 6 for the anion radical of / -alanyl-glycine at — 153°C. Depending on the peptide and pH, deamination can occur by a process involving either inter- or intramolecular electron transfer. Dissociation at other C—N bonds is also possible, leading to an amide and a fatty acid radical (20,63) this process will be referred to as deamidation or secondary deamination. As will be mentioned below, this reaction and the chemistry that follows are important for peptides and proteins. [Pg.133]

The spectrum shown can be compared with that of the propionic acid radical formed independently or by the deamination of alanine. This sequence is representative of several acetylamino acids studied. [Pg.136]

Abstraction of H from the Peptide by Carbon Radicals. The carbon radicals derived from deamination, deamidation, and decarboxylation react subsequently with the peptides to abstract hydrogen, forming the more stable a-carbon peptide radicals (63). This reaction can be demonstrated in irradiated ices containing acetylamino acids. Continuing with the N-acetylalanine example, one can also see in Figure 7 that upon further annealing to — 50 °C, another radical appears corresponding to reaction 19 ... [Pg.136]

The most established method for enzymatic L-amino acid synthesis is the resolution of racemates of N-acetylamino acids by acylase I from AspergiUus oryzae fungus. The N-acetyl-L-amino acid is cleaved to yield L-amino acid whereas the N-acetyl-D-amino acid does not react. After separation of the L-amino acid through ion exchange chromatography or crystallization, the remaining N-acetyl-D-amino acid can be... [Pg.757]

Esterification with diazomethane. Treatment with acetic anhydride Methyl esters of N-acetylamino acids 18,19... [Pg.17]

Table I. y-ray Induced Degradation of Solid N-acetylamino Acids, GH3CONHCH(R)COOH ... Table I. y-ray Induced Degradation of Solid N-acetylamino Acids, GH3CONHCH(R)COOH ...
Table III. Ammonia and Fatty Acid Yields in the y-Radiolysis of Aliphatic N-Acetylamino Acid... Table III. Ammonia and Fatty Acid Yields in the y-Radiolysis of Aliphatic N-Acetylamino Acid...
Furthermore, Kawase" found that 7V-acetylamino acids 71 react with TFAA in the presence of pyridine to form l,4-oxazin-3-ones 75, as summarized below (Fig. 4.22). The only unprecedented step in this proposed mechanism is the final transformation of 74 to 75. [Pg.487]


See other pages where Acetylamino acid is mentioned: [Pg.85]    [Pg.237]    [Pg.80]    [Pg.173]    [Pg.175]    [Pg.100]    [Pg.379]    [Pg.273]    [Pg.162]    [Pg.1450]    [Pg.474]    [Pg.129]    [Pg.741]    [Pg.787]    [Pg.73]    [Pg.760]    [Pg.1220]    [Pg.388]    [Pg.309]    [Pg.195]    [Pg.62]    [Pg.126]   
See also in sourсe #XX -- [ Pg.3 , Pg.4 , Pg.62 , Pg.195 ]

See also in sourсe #XX -- [ Pg.3 , Pg.4 , Pg.62 , Pg.195 ]

See also in sourсe #XX -- [ Pg.117 ]




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Acetylamino acetic acid

Chiral recognition molecule N-acetylamino acid

N-acetylamino acid racemase

N-acetylamino acids

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