DL-tryptophan

The first observation of the enantioselective properties of an albumin was made in 1958 (28) when it was discovered that the affinity for L-tryptophan exceeded that of the D-enantiomer by a factor of approximately 100. This led to more studies in 1973 of the separation of DL-tryptophan [54-12-6] C22H22N2O2, on BSA immobilized to Sepharose (29). After extensive investigation of the chromatographic behavior of numerous racemic compounds under different mobile-phase conditions, a BSA-SILICA hplc column (Resolvosil-R-BSA, Macherey-Nagel GmvH, Duren, Germany) was... 

Appllca.tlons. Various A/-derivatives of amino acids (qv) are resolvable on BSA columns. These /V-amino acid derivatives include ben2enesulfonyl-, phthalimido-, S-dimethylarnino-l-naphthalenesulfonyl- (DANSYL-), 2,4-dinitrophenyl- (DNP-), and 2,3,6-trinitrophenyl- (TNP-) derivatives (30). Amines such as Prilocain, ( )-2-(prop5lamino)-(9-propiono-toluidide, a local anesthetic (Astra Pharm. Co.), are also resolved on BSA. The aromatic amino acids DL-tryptophan, 5-hydroxy-DL-tryptophan, DL-kynurenine [343-65-7] C qH 2N 2 3 3-hydroxy-DT.-kynurenine [484-78-6] and dmgs... 

C HpNsO, 133186-23-9) see Aciclovir iV-acetyl-S-benzyloxy-DL-tryptophan (C2, H2,N204 53017-51-9) see Oxitriptan iV-aeetyl-lV,0-bis(trimethylsilyl)cytosine... 

Nakamura, M., Kiyohara, S., Saito, K. Sugita, K., and Sugo, T., High resolution of DL-tryptophan at high flow rates using a bovine serum albumin-multilayered porous hollow-fiber membrane, Anal. Chem., 71, 1323, 1999. 

No mutation leading to arginine prototrophy or 5-methyl-DL-tryptophan resistance were detected. Topical application on embryos and larvae Volume not clearly stated... 

The monolayer structures for tryptophan are consistent with one and two molecules per unit cell, respectively, for Cu(100) and Cu(l 11). The structures observed for D- and L-tryptophan are related by mirror inversion which is consistent with the symmetry relationship between the two molecules. A mixture of the optical isomers, DL-tryptophan does not form an ordered monolayer, thus there is no segregation or cooperative interaction between the different isomers. 

In addition to forming ordered monolayer structures, ordered multilayer films of several hundred Angstrom thickness were also grown for tryptophan. Ordered multilayers could be grown for DL-tryptophan even though the DL-tryptophan monolayer was disordered. 

Experiment 5.184 dl-TRYPTOPHAN [2-Amino-3-(3-indolyl)propanoic acid]... 

FIGURE 2 Enantiomeric resolution of DL-tryptophan on defated BSA-succinoyl-aminoethyl-agrose column (0.9x25cm) using borate buffer (0.1 M). (From Ref. 9.)... 

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