- Enzymatic synthesis of oligopeptides in mixed reverse micelles
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Some oligopeptide derivatives were successfully synthesized in 56-88% yield by α-chymotrypsin in AOT-Brij30/n-heptane mixed reverse micelles. The reaction conditions such as W0 value, reaction time and the concentration of enzyme in the water p
- Xing, Guo-wen,Liu, Dao-jun,Ye, Yun-hua,Ma, Ji-ming
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p. 1971 - 1974
(2007/10/03)
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- Carbohydrate Protease Conjugates: Stabilized Proteases for Peptide Synthesis
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The synthesis of oligopeptides using stable carbohydrate protease conjugates (CPCs) was examined in acetonitrile solvent systems.CPC was used for the preparation of peptides containing histidine, phenylalanine, tyrosine, and tryptophan in the P1 position in 60-93percent yield.The CPC was used to synthesize peptides containing both hydrophilic and hydrophobic amino acids.The P2 specificity of papain for aromatic residues was utilized for the 2 + 3 coupling of Z-Tyr-Gly-OMe to H2N-Gly-Phe-Leu-OH to generate the leucine enkephalin derivative in 79percent yield.Although papain is nonspecific for the hydrolysis of N-benzyloxycarbonyl amino acid methyl esters in aqueous solution, the rates of synthesis for these derivatives with nucleophile leucine tert-butyl ester differed by nearly 2 orders of magnitude.CPC was used to prepare the aspartame precursor Z-Asp-Phe-OMe in 90percent yield.The increased stability of CPCs prepared from periodate-modified poly(2-methacrylamido-2-deoxy-D-glucose), poly(2-methacrylamido-2-deoxy-D-galactose), and poly(5-methacrylamido-5-deoxy-D-ribose), carbohydrate materials designed to increase the aldehyde concentration in aqueous solution, suggests that the stability of CPCs is directly related to the aldehyde concentration of the carbohydrate material.Periodate oxidation of poly(2-methacrylamido-2-deoxy-D-glucose) followed by covalent attachment to α-chymotrypsin gave a CPC with catalytic activity in potassium phosphate buffer at 90 deg C for 2 h.
- Wartchow, Charles A.,Wang, Peng,Bednarski, Mark D.,Callstrom, Matthew R.
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p. 2216 - 2226
(2007/10/02)
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- Facile Enzymatic Synthesis of N-Acyl-enkephalin Amides
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A novel three step protease catalysed synthesis of enkephalin precursors from simple readily available substrates is described.
- Gill, Iqbal,Vulfson, Evgeny N.
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p. 667 - 668
(2007/10/02)
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- PEPTIDE SYNTHESIS BY USING PHENYLPHOSPHONIC ESTER AS A COUPLING REAGENT
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Synthesis of peptides containing various functions was efficiently accomplished by treatment of the tetrabutylammonium salts of N-protected amino acids (or peptides) with amino acid esters in the presence of bis(o- or p-nitrophenyl) phenylphosphonate.Synthesis of leucine-enkephalin was successfully achieved by the above method employing a (3+2) or (4+1) fragment coupling approach.
- Watanabe, Yutaka,Morito, Naoya,Kamekawa, Ken-ichi,Mukaiyama, Teruaki
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