Photolysis of poly(amino acid)s at 77K: An ESR study

Hill D.J.T., O'Donnell J.H., Pomery P.J. and Whittaker A.K. (1985) Photolysis of poly(amino acid)s at 77K: An ESR study. Polymer Degradation and Stability, 10 1: 15-23. doi:10.1016/0141-3910(85)90017-5


Author Hill D.J.T.
O'Donnell J.H.
Pomery P.J.
Whittaker A.K.
Title Photolysis of poly(amino acid)s at 77K: An ESR study
Journal name Polymer Degradation and Stability   Check publisher's open access policy
ISSN 0141-3910
Publication date 1985-01-01
Sub-type Article (original research)
DOI 10.1016/0141-3910(85)90017-5
Volume 10
Issue 1
Start page 15
End page 23
Total pages 9
Subject 1605 Policy and Administration
2507 Polymers and Plastics
Abstract The mechanism of the ultraviolet (λ > 250 nm) degradation of poly(amino acid)s has been studied by ESR spectroscopy at 77 K. In the aliphatic poly(amino acid)s of glycine, alanine and valine, absorption of energy occurs predominantly in the peptide group, and the initial degradation reaction is scission of the CONH bond. The imino radical, ·NHCHR, abstracts the main chain H from the CHR group, or the tertiary H from valine, to give secondary carbon radicals. The acyl radical, CHRCO·, readily loses CO to form a chain-end radical, CHR·. The aromatic poly(amino acid)s of phenylalanine and tyrosine absorb energy mainly in the phenyl chromophore and bond scission occurs in the side chain. The mechanism of photolysis of the poly(amino acid)s differs from that of the N-acetyl amino acids (except for tyrosine) due to the presence of the labile carboxyl group.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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Created: Tue, 16 Aug 2016, 11:30:29 EST by System User