title: Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR.
abstract: The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of metabolic transformations. Hyperpolarization via dissolution DNP circumvents part of the sensitivity issues thanks to the large out-of-equilibrium nuclear magnetization stemming from the electron-to-nucleus spin polarization transfer. The high NMR signal obtained can be used to monitor chemical reactions in real time. The downside of hyperpolarized NMR resides in the limited time window available for signal acquisition, which is usually on the order of the nuclear spin longitudinal relaxation time constant, T1, or, in favorable cases, on the order of the relaxation time constant associated with the singlet-state of coupled nuclei, TLLS. Cellular uptake of endogenous molecules and metabolic rates can provide essential information on tumor development and drug response. Numerous previous hyperpolarized NMR studies have demonstrated the relevancy of pyruvate as a metabolic substrate for monitoring enzymatic activity in vivo. This work provides a detailed description of the experimental setup and methods required for the study of enzymatic reactions, in particular the pyruvate-to-lactate conversion rate in presence of lactate dehydrogenase (LDH), by hyperpolarized NMR.
authors.affiliation: LCBPT - UMR8601, Institut de Chimie, Université Paris Descartes; balzan.riccardo@parisdescartes.fr.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Balzan
authors.affiliation: LCBPT - UMR8601, Institut de Chimie, Université Paris Descartes.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Fernandes
authors.affiliation: Institute of Physics of Biological Systems, EPFL.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Comment
authors.affiliation: PARCC - INSERM U970, Université Paris Descartes.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Pidial
authors.affiliation: PARCC - INSERM U970, Université Paris Descartes.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Tavitian
authors.affiliation: LCBPT - UMR8601, Institut de Chimie, Université Paris Descartes; paul.vasos@parisdescartes.fr.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Vasos
mesh_terms: D019344:Lactic Acid / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D011522:Protons; D019289:Pyruvic Acid / Q000378:metabolism; D012995:Solubility; D013997:Time Factors
chemical_list: D011522:Protons; D019344:Lactic Acid; D019289:Pyruvic Acid