In Chapter I of this thesis, the -subunit mechanism of tryptophan synthase is
investigated. We explored the addition of indole to the preformed aminoacrylate Lserine-enzyme complex to form an indolenine quinonoid intermediate. A kinetic isotope effect (KIE) is observed in the tautomerization of the indolenine quinonoid intermediate, and the KIE is dependent on the presence of allosteric ligands.
Chapter II presents the excited state tautomerization of 4-azaindole and 5-
azaindole in certain solvent conditions. The N1-H tautomer is lower in energy in the
ground state, while the other tautomer is lower in energy in the excited state.
