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L-leucine 57

The influence of a large number of oc-amino acids on the values of and k at have been determined. These a-amino acids included glycine, L-valine, L-leucine, L-phenylalanine, L-tyrosine, L-tryptophan, NOrmethyl-L-tryptophan (L-abrine), N-methyl-L-tyrosine, N,N-dimethyl-L-tyrosine and p -me thoxy-N-me thyl -L -phenyl al anine. [Pg.175]

The amino acids L-leucine, T-phenylalanine, L-tyrosine, and L-tryptophan all taste bitter, whereas their D-enantiomers taste sweet (5) (see Amino ACIDS). D-Penicillamine [52-67-5] a chelating agent used to remove heavy metals from the body, is a relatively nontoxic dmg effective in the treatment of rheumatoid arthritis, but T.-penicillamine [1113-41 -3] produces optic atrophy and subsequent blindness (6). T.-Penicillamine is roughly eight times more mutagenic than its enantiomer. Such enantioselective mutagenicity is likely due to differences in renal metaboHsm (7). (R)-ThaHdomide (3) is a sedative—hypnotic (3)-thaHdomide (4) is a teratogen (8). [Pg.237]

Thraustomycin. Thraustomycin and P-thraustomycin are isolated from S. exfoliatus (4). Although their stmctures have not been totally elucidated, hydrolysis of thraustomycin shows that it contains equimolar quantities of adenine, L-leucine, and a tetrahydroxymonocarboxyhc acid. Thraustomycin is a potent inhibitor of the fungus, Af. hiemallis (+), but does not inhibit bacteria. [Pg.122]

Ubenimex, [(2(3),3(R))-3-amino-2-hydroxy-4-phenylbutanoyl]-L-leucine, was isolated as an inhibitor of aminopeptidases, on which it acts as a strong, reversible transition-state analogue inhibitor (293). Analogues of ubenimex have been made and some other aminopeptidase inhibitors, not all of them peptides, have been isolated from streptomycetes (294—296). [Pg.159]

N-Benzoyl L-leucylglyclne ethyl ester (3). N-Benzoy-L-leucine 1 (0.235 g, 1 mmol) and glycine ethyl ester hydrochloride 2 (0 1534 g, 1.1 mmol) in OMF (10 mL) under stirring vyas treated with diethylphosphoryl cyanide 3 (0.179 g, 1.1 mmol) In OMF at 0°C, followed by the addition of triethylamine (0.212 g, 2 1 mmoO. The mixture was stirred for 30 min at 0°C and 4 h at 20 C The reaction mixture was diluted with PhH-EtOAc, washed with 5% HCI, water, 5% NaHCOs solution and bnne. Evaporation of the solvent gave crude 4 which after sIDca gel chromatography afforded 0.271 g of 4 (66%) (pure L), mp 1S8-160°C. [Pg.430]

A -Acetyl-6A -methyl-L-leucine amide [32483-15-1] M 186.3. Recrystd from EtOH/hexane mixture. [Pg.91]

If, however, the /7-nitrophenyl ester of iV-henzoyl-L-leucine is treated with 1-methyl-piperidine in chloroform for 30 min and then coupled with glycine ethyl ester, the dipeptide isolated is almost completely racemic. Furthermore, treatment of the p-nitrophenyl ester of iV-benzoyl-L-leucine with 1-methylpiperidine alone leads to the formation of a crystalline material, C13H15NO2, having strong IR bands at 1832 and 1664 cm . Explain these observations, and suggest a reasonable stmcture for the crystalline product. [Pg.499]

Glycine (hRf 20—25), DL-alanine (hRf 30 — 35), DL-valine hRf 45 — 50) and L-leucine (HRf 55—60) yielded red-violet chromatogram zones on a pale yellow background. The detection limits for these amino acids were 5 ng substance per... [Pg.267]

A recent report describes the conversion of A-formyl- and N-acetyl-L-leucine into optically active azlactones with dicyclohexyl-carbodiimide (DCC) [Eq. (29)]. Other cyclization reagents, e.g. acetic anhydride, POCI3, SOCI2, and polyphosphoric acid, cause racemiza-tion. These azlactones react with optically active amino acid esters to give esters of dipeptides with retention of activity. [Pg.97]

S,N-Ditrityl-L-cysteine diethylamine selt L-Tyrosine lower alkyl ester L-lsoleucine lower alkyl ester Benzyl-L-proline hydrochloride L-Leucine lower alkyl ester Ammonia Hydrogen chloride Glycine lower alkyl ester... [Pg.1155]

It is a peptide containing 27 amino acid residues containing the amino acids L-histidine (His) L-aspartic acid (Asp) L-serine (Ser) glycine (Gly) L-threonine (Thr) L-phenyl-alanine (Phe) L-glutamic acid (Glu) L-glutamine [Glu(NHj)] L-leucine (Leu) L-arginine (Arg) L-alanine (Ala) and L-valinamide (Va -NHj). [Pg.1371]

For the separation of D,L-leucine, Ding et al. [62] used poly(vinyl alcohol) gel-coated microporous polypropylene hollow fibers (Fig. 5-11). An octanol phase containing the chiral selector (A-n-dodecyl-L-hydroxyproline) is flowing countercur-rently with an aqueous phase. The gel in the pores of the membrane permits diffusion of the leucine molecules, but prevents convection of the aqueous and octanol phase. At a proper selection of the flow ratios it is possible to achieve almost complete resolution of the D,L-leucine (Fig. 5-12). [Pg.139]

L-Leucine L-Amino-acid oxidase RCOCOO, NH4+, h2o2 Tris pH 7 NH/-glass ... [Pg.255]


See other pages where L-leucine 57 is mentioned: [Pg.86]    [Pg.87]    [Pg.102]    [Pg.876]    [Pg.882]    [Pg.892]    [Pg.895]    [Pg.562]    [Pg.787]    [Pg.923]    [Pg.60]    [Pg.146]    [Pg.269]    [Pg.282]    [Pg.285]    [Pg.289]    [Pg.289]    [Pg.292]    [Pg.293]    [Pg.294]    [Pg.297]    [Pg.278]    [Pg.96]    [Pg.96]    [Pg.5]    [Pg.9]    [Pg.1156]    [Pg.1156]    [Pg.1156]    [Pg.6]    [Pg.76]    [Pg.140]    [Pg.9]    [Pg.10]    [Pg.18]    [Pg.19]   
See also in sourсe #XX -- [ Pg.1111 , Pg.1113 , Pg.1119 ]




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Acetyl-L-leucine

Benzoyl-L-leucine

D- and l- Leucine

D-Alanyl-L-leucine

Dansyl-L-leucine-modified

Disorders of L-leucine metabolism

Glycyl-L-leucine

Glycyl-L-leucine dipeptidase

Immobilized poly-L-leucine

L-Leucine 2,3-aminomutase

L-Leucine benzyl ester

L-Leucine lower alkyl ester

L-Leucine, -4-hydroxy-5-methyl-3-oxohexanoylesters

L-Leucine, -4-hydroxy-5-methyl-3-oxohexanoylesters synthesis

L-Leucine, methyl ester, hydrochloride

L-leucine 5-hydroxylase

L-leucine dehydrogenase

L-terf-Leucine

L-tert-leucine

N-succinyl L-leucine 3-hydroxylase

Poly-L-leucine

Secondary Products Derived from L-Leucine

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