In:
ELECTROPHORESIS, Wiley, Vol. 34, No. 18 ( 2013-09), p. 2666-2673
Kurzfassung:
Isomerization and enantiomerization of A sp in the tetrapeptide A la‐ P he‐ A sp‐ G ly OH are studied at p H 10 and 80°C as well as 25°C. CE ‐ MS allowed the distinction between α‐ A sp and β‐ A sp linkages in degradation products based on the ratio of the b and y fragment ions. Besides isomerization and enantiomerization of A sp, enantiomerization of A la and P he was also observed at both temperatures by chiral amino acid HPLC analysis using M arfey's reagent for derivatization. The rate of enantiomerization of the amino acids proceeded in the order A sp 〉 A la 〉 P he. The CE assay was validated with respect to linearity, LOQ , LOD , and precision and employed to characterize the time course of the degradation of the tetrapeptide upon incubation in borate buffer, p H 10. Isomerization to β‐ A sp peptides was identified as the major degradation reaction. The configuration of A sp or A la affected the half‐life of the starting peptide to a minor extent but did not influence the distribution of the individual products under equilibrium conditions at 80°C. Degradation at 25°C proceeded very slowly so that the equilibrium was not reached after 245 days.
Materialart:
Online-Ressource
ISSN:
0173-0835
,
1522-2683
DOI:
10.1002/elps.201200685
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2013
ZDB Id:
1475486-1
SSG:
12
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