632. Synthetic polypeptides. Part II. Polyglutamic acid

Hanby, W. E.; Waley, S. G.; Watson, J.

doi:10.1039/jr9500003239

Cited by 125 publications

(55 citation statements)

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“…Hydrogenation would appear to be the most attractive method, however, it is only effective for chains less than 10 kDa in mass. Larger PBLG chains adopt stable helical conformations that prevent access of the hydrogenation catalyst to the ester groups [50,51]. Ester cleavage using trimethylsilyl iodide was found to give clean conversion to the readily hydrolyzed trimethylsilyl ester, without any racemization or chain cleavage [52].…”

Section: Polypeptide Deprotection and Purificationmentioning

confidence: 97%

“…Use of strong acid (e.g., gaseous HBr or HBr in acetic acid) avoids any racemization, but is known to lead to significant chain cleavage arising from protonation of side-chain ester groups that react with the amide backbone [49]. Basic conditions avoid this reaction, but can lead to significant racemization unless the amount of base is carefully controlled [50,51]. Hydrogenation would appear to be the most attractive method, however, it is only effective for chains less than 10 kDa in mass.…”

Section: Polypeptide Deprotection and Purificationmentioning

confidence: 97%

“…The unique chemistry of these initiators and NCA monomers also allows NCA monomers to be polymerized in any order, which is a challenge in most vinyl copolymerizations, and the robust chain-ends allow the preparation of copolypeptides with many block domains (e.g., more than four). The self-assembly of these block copolypeptides has also been investigated (e.g., to direct the biomimetic synthesis of ordered silica structures [48]) for formation of polymeric vesicular membranes [49][50][51], or for preparation of self-assembled polypeptide hydrogels [52] and nanoscale emulsion droplets [53]. Furthermore, poly(L-lysine)-block-poly(L-cysteine) block copolypeptides have been used to generate hollow, organic-inorganic hybrid microspheres composed of a thin inner layer of gold nanoparticles surrounded by a thick layer of Synthesis of Polypeptides by Ring-Opening Polymerizationsilica nanoparticles [54].…”

Section: Block Copolypeptidesmentioning

confidence: 99%

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Synthesis of Polypeptides by Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides

Cheng

Deming

2011

Topics in Current Chemistry

135

111

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This chapter summarizes methods for the synthesis of polypeptides by ring-opening polymerization. Traditional and recently improved methods used to polymerize α-amino acid N-carboxyanhydrides (NCAs) for the synthesis of homopolypeptides are described. Use of these methods and strategies for the preparation of block copolypeptides and side-chain-functionalized polypeptides are also presented, as well as an analysis of the synthetic scope of different approaches. Finally, issues relating to obtaining highly functional polypeptides in pure form are detailed.

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Section: Polypeptide Deprotection and Purificationmentioning

confidence: 97%

Section: Polypeptide Deprotection and Purificationmentioning

confidence: 97%

Section: Block Copolypeptidesmentioning

confidence: 99%

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Synthesis of Polypeptides by Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides

Cheng

Deming

2011

Topics in Current Chemistry

135

111

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“…A somewhat remote chemical analogy may be seen in the rearrangement of glutamic acid anhydride to 2-pyrrolidone-5-carboxylic acid [66,67].…”

Section: The Enzyme-catalyzed Reaction and The Interconversion Of Aldmentioning

confidence: 99%

Reaction Mechanism of d-Galactose Dehydrogenases from Pseudomonas saccharophila and Pseudomonas fluorescens. Formation and Rearrangement of Aldono-1,5-lactones

1974

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1. b-D-Galactopyranose has been shown by specificity studies and by gas-liquid chromatographic investigations to be the substrate of the D-galactose dehydrogenases from Pseudomonas sacchurophilu and from Pseudomonas fluorescens.2. cc-~-Galactopyranose and the two ring-isomeric D-galactofuranoses are oxidized, at high enzyme concentrations, only after their rate-limiting isomerization into the b-D-pyranose. The open-chained aldehyde form of D-galactose has been likewise excluded as substrate.3. D-Galactono-l,5-lactone has been shown by gas-liquid chromatography to be the immediate product of the enzymatic dehydrogenation of D-galactose and identified by combined gas-liquid chromatography -mass spectrometry of the isolated trimethylsilylated derivative.4. The primarily formed D-galactono-l,5-lactone rearranges non-enzymatically to the corresponding D-galactono-l,4-lactone by an intramolecular rearrangement without the participation of the open-chained D-galactonate. This rearrangement is strongly dependent on the pH-value, having a first-order rate constant k = 1.0 min-' at pH 6.8 under the conditions used. were determined at pH 6.8 under the conditions used, enabling the estimation of the apparent equilibrium constant for the reaction catalyzed by the enzyme6. Results analogous to those with D-galactose were obtained from investigations with the homeomorphic L-arabinose. The pyranose ring with the hydroxyl group at carbon-1 in the equatorial position is likewise the only substrate, and the immediate product, the 1,5-lactone, also rearranges subsequently to the corresponding 1,4-lactone, having a first-order rate constant k = 0.22 min-l at pH 6.8 under the conditions used. The ~-arabinono-1,5-lactone has also been identified by gas-liquid chromatography -mass spectrometry of the trimethylsilylated derivative.

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“…We have observed that the chiroptical properties of the polyacid and of the parent ester polymer in 0.2M NaOH remain unchanged after 2 weeks. This behavior is substantially different from that of poly(L-glutamic acid), whose chiroptical properties in aqueous alkaline solution are substantially affected even after 24 h. 7 The CD spectrum of poly(N-methylglutamic acid) in aqueous solution at neutral pH is shown in Fig. 1.…”

mentioning

confidence: 99%

N‐substitutes poly‐α‐amino acids. III. Synthesis and conformational properties of poly(N‐methyl‐L‐glutamic acid)

Cosani¹,

Terbojevich²,

Palumbo³

et al. 1982

Biopolymers

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In previous p a p e r~, l -~ we have investigated the conformational properties in solution of N-methyl derivatives of esters of poly(L-glutamic acid) in solution. It was found that despite of the absence of amide hydrogen bonds, in a variety of solvents, including trifluoracetic acid, these polymers form a surprisingly stable ordered conformation, very similar to that of poly(N-methylalanine), i.e., a right-handed helix with $J and 1c, dihedral angles of about 30' and 240°, respectively. This structure has been proposed on the basis of conformational

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632. Synthetic polypeptides. Part II. Polyglutamic acid

Cited by 125 publications

References 0 publications

Synthesis of Polypeptides by Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides

Synthesis of Polypeptides by Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides

Reaction Mechanism of d-Galactose Dehydrogenases from Pseudomonas saccharophila and Pseudomonas fluorescens. Formation and Rearrangement of Aldono-1,5-lactones

N‐substitutes poly‐α‐amino acids. III. Synthesis and conformational properties of poly(N‐methyl‐L‐glutamic acid)

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