Observation and Kinetic Characterization of Transient Schiff Base Intermediates by CEST NMR Spectroscopy.

ABSTRACT: In aqueous solution, many biochemical reaction pathways involve reaction of an aldehyde with an amine, which progresses through generally unstable, hydrated and dehydrated, Schiff base intermediates that often are unobservable by conventional NMR. There are 4 states in the relevant equilibrium: 1) gem-diol, 2) aldehyde, 3) hemiaminal, and 4) Schiff base. For the reaction between protein amino groups and DOPAL, a highly toxic metabolite of dopamine, the ¹ H resonances of both the hemiaminal and the dehydrated Schiff base can be observed by CEST NMR, even when their populations fall below 0.1 %. CEST NMR reveals the quantitative exchange kinetics between reactants and Schiff base intermediates, explaining why the Schiff base NMR signals are rarely observed. The reactivity of DOPAL

SUBMITTER: Ramanujam V 

PROVIDER: S-EPMC8829840 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature