Title:
Well-Defined Homopolypeptides, Copolypeptides, and Hybrids of Poly(l-proline)
Languages of Item:
English
Abstract:
l-Proline is the only, out of 20 essential, amino acid that contains a cyclized substituted α-amino group (is formally an imino acid), which restricts its conformational shape. The synthesis of well-defined homo- and copolymers of l-proline has been plagued either by the low purity of the monomer or the inability of most initiating species to polymerize the corresponding N-carboxy anhydride (NCA) because they require a hydrogen on the 3-N position of the five-member ring of the NCA, which is missing. Herein, highly pure l-proline NCA was synthesized by using the Boc-protected, rather than the free amino acid. The protection of the amine group as well as the efficient purification method utilized resulted in the synthesis of highly pure l-proline NCA. The high purity of the monomer and the use of an amino initiator, which does not require the presence of the 3-N hydrogen, led for the first time to well-defined poly(l-proline) (PLP) homopolymers, poly(ethylene oxide)-b-poly(l-proline), and poly(l-proline)-b-poly(ethylene oxide)-b-poly(l-proline) hybrids, along with poly(γ-benzyl-l-glutamate)-b- poly(l-proline) and poly(Boc-l-lysine)-b-poly(l-proline) copolypeptides. The combined characterization (NMR, FTIR, and MS) that results for the l-proline NCA revealed its high purity. In addition, all synthesized polymers exhibit high molecular and compositional homogeneity. © 2011 American Chemical Society.
Authors:
Manos Gkikas
Hermis Iatrou
Nikolaos S. Thomaidis
Paschalis Alexandridis
Nikos Hadjichristidis
Journal:
Biomacromolecules
Publisher:
American Chemical Society (ACS)
Keywords:
Amine groups; Amino group; Compositional homogeneity; Copolypeptides; Ethylene oxides; Free amino acids; FTIR; High purity; L-proline; Low purity; N-carboxy anhydrides; Purification method; Synthesized polymers, Carboxylic acids; Ethylene; Hydrogen; Monomers; Polyethylene oxides; Polymers, Amino acids, amine; amino acid; copolypeptide; homopolypeptide; hydrogen; monomer; n carboxy anhydride; poly(boc lysine)beta poly(proline); poly(ethylene oxide)beta poly(proline); poly(gamma benzyl glutamate)beta poly(proline); poly(proline) beta poly(ethylene oxide) beta poly(proline); polymer; polypeptide; polyproline; unclassified drug, amino acid sequence; article; hybrid; infrared spectroscopy; mass spectrometry; nuclear magnetic resonance; priority journal; protein purification; synthesis, Anhydrides; Biocompatible Materials; Circular Dichroism; Drug Carriers; Lysine; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Conformation; Peptides; Polyethylene Glycols; Proline; Spectroscopy, Fourier Transform Infrared; Temperature
Main subject category:
Science
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