Extended para-hydrogenation monitored by NMR spectroscopy

Abstract

A system that provides a sustained hyperpolarized (1)H NMR signal in an aqueous medium is reported. The enhanced signal lasts much longer than typical (1)H T(1) values, uncovering new possibilities for implementing hyperpolarized (1)H NMR/MRI experiments or performing kinetics studies that would not otherwise be detectable.

Peptide Hydrogenation and Labeling with Parahydrogen

“…One attractive choice to address this issue is the use of isotopically labeled molecules. [5] As an example of applying PHIP methods to molecules typical of those found in biology, we describe herein the monitoring of a homogeneous hydrogenation reaction with Rh I complexes, taking advantage of the "only parahydrogen spectroscopy" (OPSY) technique [6] for the analysis of reaction stereoselectivity and conformational dynamics of peptide units.Although in prior work the hydrogenation of a dehydroamino acid derivative was demonstrated, [7] scaling up the procedure to larger molecules is nontrivial. Recently, the use of hyperpolarized molecules has attracted much attention.…”

Versatile magnetic resonance singlet tags compatible with biological conditions

“…47 Other important elds are their utilization as Michael acceptors, with particular use in click chemistry reactions 48,49 and as precursors for imaging contrast agents. [31][32][33][34][35][36][37][38][50][51][52] In the present case, the close proximity of the acrylate protons reduces the inuence of relaxation agents such as paramagnetic species on nuclear singlet order, except at very short range. The relatively small shi difference of about 0.6 ppm between acrylate protons makes it feasible to spin-lock singlet states at high magnetic eld by applying on resonant radiofrequency irradiation.…”

“…13 Various applications of singlet states have been proposed, including the utilization of long T S times to probe slow dynamic processes in biomolecules and the binding of drugs, 6,10,[15][16][17] and as a means to support nuclear hyperpolarization in the context of molecular imaging. 18,21,23,28,[31][32][33][34][35][36][37][38][39][40][41][42][43] In some cases, the protons of biomolecules support nuclear singlet states. Examples include molecules relevant to neuroscience such as aspartate and glutamine, peptides, proteins and adenosinediphosphate (ADP).…”

Peptide Hydrogenation and Labeling with Parahydrogen

“…Although in prior work the hydrogenation of a dehydroamino acid derivative was demonstrated,7 scaling up the procedure to larger molecules is nontrivial. Herein, we sought to examine a peptide by PHIP.…”

“…We are grateful to Dr. Roman Fleysher for building the parahydrogen enrichment apparatus as part of a collaboration with Dr. Daniel K. Sodickson (Ref. 7). We would like to thank Pei Che Soon for experimental assistance during the revision.…”