Ground-state electronic destabilization via hyperconjugation in aspartate aminotransferase.
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ABSTRACT:
SUBMITTER: Griswold WR
PROVIDER: S-EPMC3425665 | biostudies-literature | 2012 May
REPOSITORIES: biostudies-literature
Publications
Ground-state electronic destabilization via hyperconjugation in aspartate aminotransferase.
Griswold Wait R WR Castro Joan Nieto JN Fisher Andrew J AJ Toney Michael D MD
Journal of the American Chemical Society 20120510 20
Binding isotope effects for l-aspartate reacting with the inactive K258A mutant of PLP-dependent aspartate aminotransferase to give a stable external aldimine intermediate are reported. They provide direct evidence for electronic ground-state destabilization via hyperconjugation. The smaller equilibrium isotope effect with deazaPLP-reconstituted K258A indicates that the pyridine nitrogen plays an important role in labilizing the Cα-H bond. ...[more]
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