Functional and structural characterization of the human indolethylamine N-methyltransferase through fluorometric, thermal and computational docking analyses.
Biology direct April 10, 2025 Matteo Ardini, Francesco Angelucci, Francesca Rea et al.
Indolethylamine N-methyltransferase (INMT) is a key enzyme in the biosynthesis of compounds like the psychedelic DMT, yet its structure and mechanism remain poorly understood. This work presents the first fluorometric steady-state assay for human INMT using quinoline as a substrate, validated by thermal shift and docking analyses. The enzyme is unstable, requiring acidic or near-neutral pH and low salt. The assay yields kinetic constants comparable to other methyltransferases, and docking shows quinoline binds at the same site as tryptamine. This method offers a simpler alternative to radioactive or mass spectrometry assays, enabling reliable kinetic studies and future investigations into enzyme mutants linked to psychiatric disorders and cancer.