Parahydrogen-Induced Methylated Amino Acid Hyperpolarization and Regression-Based Hyperpolarization Enhancement Factor Prediction

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are powerful analytical tools with diverse applications in research and medicine. However, the inherently poor signal-to-noise ratios induce technical limitations, which suppress their widespread use. Hyperpolarization enhances the NMR signals by inducing highly nonequilibrated population distributions among the nuclear spin states. We demonstrated real-time amino acid hyperpolarization using signal amplification by reversible exchange (SABRE). We aimed to hydrolyze hyperpolarized methyl esters to induce amino acid hyperpolarization. We successfully hyperpolarized 19 methylated amino acids via SABRE. This groundwork enabled the development of a predictive model for the hyperpolarization enhancement factors of methylated amino acids. The model accurately predicted the hyperpolarization of three synthetic methylated amino acids, paving the way for advanced bio-NMR and MRI applications requiring the immediate hyperpolarization of other amino acids. This research underlines the potential of hyperpolarization in overcoming the current limitations of NMR spectroscopy and MRI.