Document Detail


Poly(alpha-alkyl gamma-glutamate)s of microbial origin. 2. On the microstructure and crystal structure of poly(alpha-ethyl gamma-glutamate)s.
MedLine Citation:
PMID:  12217056     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The stereochemical microstructure and crystalline structure of nearly racemic poly(alpha-ethyl gamma,DL-glutamate) obtained by esterification of biosynthetic poly(gamma-glutamic acid) were examined by NMR, DSC, and powder X-ray diffraction. The two enantiomerically pure poly(alpha-ethyl gamma-glutamate)s, as well as the racemic stereocopolymers with random and alternating microstructure, were prepared by chemical synthesis and studied in parallel to help in the interpretation of the data. The (13)C NMR analysis revealed that biosynthetic poly(alpha-ethyl gamma,DL-glutamate) consists of a block stereocopolymer accompanied by minor amounts of a mixture of the two optically pure homopolymers. The polymer is crystalline, with a degree of crystallinity and crystal structure essentially similar to those displayed by the optically pure polymers but clearly different from the alternating copolymer. Conversely, the racemic stereocopolymer with a random microstructure prepared by chemical synthesis is amorphous. The crystal structure of the racemic mixture of the D- and L-homopolymers seems to be very close to that of the biosynthetic stereocopolymer, although some indications suggesting the existence of a stereocomplex were found.
Authors:
Antxon Martínez de Ilarduya; Najim Ittobane; Marta Bermúdez; Abdelilah Alla; Mustafa El Idrissi; Sebastián Muñoz-Guerra
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biomacromolecules     Volume:  3     ISSN:  1525-7797     ISO Abbreviation:  Biomacromolecules     Publication Date:    2002 Sep-Oct
Date Detail:
Created Date:  2002-09-09     Completed Date:  2003-07-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100892849     Medline TA:  Biomacromolecules     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1078-86     Citation Subset:  IM    
Affiliation:
Departament d'Enginyería Química, Universitat Politécnica de Catalunya E.T.S. d'Enginyers Industrials de Barcelona, Diagonal 647, 08028 Barcelona, Spain.
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MeSH Terms
Descriptor/Qualifier:
Bacteria / chemistry
Calorimetry, Differential Scanning
Crystallization
Esterification
Molecular Structure
Nuclear Magnetic Resonance, Biomolecular
Polyglutamic Acid / chemistry*
Stereoisomerism
X-Ray Diffraction
Chemical
Reg. No./Substance:
25513-46-6/Polyglutamic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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