Parahydrogen-induced polarization enables the single-scan NMR detection of a 236 kDa biopolymer at nanomolar concentrations

Nuclear magnetic resonance (NMR) experiments utilizing parahydrogen-induced polarization (PHIP) were performed to elucidate the PHIP activity of the synthetic 236 kDa biopolymer poly-& gamma;-(4-propargyloxy)-benzyl-L-glutamate) (PPOBLG). The homopolypeptide was successfully hyperpolarized and the enhanced signals were detected in 11.7 T solution NMR as a function of the PPOBLG concentration. The hydrogenation with parahydrogen caused signal enhancements of 800 and more for the vinyl protons of the side chain at low substrate concentration. As a result of this high enhancement factor, even at 13 nM of PPOBLG, a single scan H-1-NMR detection of the hyperpolarized protons was possible, owing to the combination of hyperpolarization and density of PHIP active sites.

Automated summary

Nuclear magnetic resonance (NMR) experiments using parahydrogen-induced polarization (PHIP) were conducted to investigate the activity of the synthetic biopolymer poly-γ-(4-propargyloxy)-benzyl-L-glutamate) (PPOBLG). The homopolypeptide was successfully hyperpolarized and the enhanced signals were detected in 11.7 T solution NMR as a function of PPOBLG concentration. Hydrogenation with parahydrogen resulted in signal enhancements of over 800 times for the vinyl protons of the side chain at low substrate concentration. Due to the high enhancement factor, even at a concentration of 13 nM PPOBLG, the hyperpolarized protons could be detected with a single scan H-1-NMR, thanks to the combination of hyperpolarization and density of PHIP active sites.