Indirect Detection of Enzymatic Processes by Hyperpolarized NMR: Temporal Information, Enhanced Spectral Resolution and Slow Spin Relaxation

Talia Harris¹, Patrick Giraudeau¹, Lucio Frydman¹

The outstanding sensitivity arising from ex situ DNP has triggered high expectations concerning the in vivo monitoring of metabolism and disease. So far such gains have materialized for experiments focusing on low-γ nuclei, whose relatively long T₁s enables them to withstand the transfer from the cryogenic hyperpolarizer to the reacting centers of interest. This study demonstrates that, when suitably merged with spatially-encoded methods, also indirectly-detected ¹H NMR spectroscopy can be exploited in time-resolved hyperpolarized analyses. The principles and opportunities opened by this approach are exemplified by Cholines phosphorylation by Choline Kinase, and by Acetylcholines hydrolization by Acetylcholine Esterase.