Toward Quantitative Measurements of Enzyme Kinetics by Dissolution Dynamic Nuclear Polarization.

Dissolution dynamic nuclear polarization (D-DNP) experiments enabled us to study the kinetics of the enzymatic phosphorylation reaction of glucose to form glucose-6-phosphate (G6P) by hexokinase (HK), with or without the presence of an excess of G6P, which is known to be an inhibitor of the enzyme. Against all expectations, our observations demonstrate that the phosphorylation of both α and β glucose anomers occurs with comparable kinetics. The catalytic constant of the reaction was estimated based on a simple kinetic model tailored for hyperpolarized systems.