Researchers have developed a nanopore-based, single-molecule platform capable of tracking multiple metabolites in the catecholamine biosynthetic pathway in real time. The platform distinguishes six key metabolites along the pathway from phenylalanine to adrenaline and monitors their dynamic changes during the enzymatic cascade by integrating two orthogonal molecular recognition mechanisms into a single MspA nanopore system.

The study, conducted by Prof. WU Hachen of the Institute of Chemistry of the Chinese Academy of Sciences and Prof. LIU Lei of Xihua University, was published inNature Nanotechnology on Sept. 1.

Catecholamines, including dopamine, noradrenaline (also known as norepinephrine), and adrenaline (also known as epinephrine), are essential neurotransmitters and hormones that regulate neural and endocrine functions. Disruption of their biosynthesis is associated with a broad range of neurological, psychiatric, and metabolic disorders. However, conventional analytical methods often lack the temporal resolution and sensitivity required to dynamically track multiple metabolites throughout an entire enzymatic pathway. Existing nanopore sensing approaches have also largely focused on individual analytes, making real-time monitoring of complete metabolic cascades challenging.

The researchers integrated two orthogonal molecular recognition mechanisms into a single MspA nanopore system. This platform distinguishes six key metabolites, from phenylalanine to adrenaline, and tracks their dynamic changes throughout the enzymatic cascade.

Using this platform, researchers identified the TH-catalyzed conversion of tyrosine to L-DOPA as the rate-limiting step. They also revealed efficient substrate channeling between tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC).

They also found that the accumulation of monoiodotyrosine markedly inhibits TH activity and reduces the production of downstream catecholamines. The finding suggests a potential mechanism underlying impaired catecholamine biosynthesis in DEHAL1 deficiency.

This work expands the capabilities of nanopore sensing from single-analyte detection to dynamic analysis of complete metabolic pathways, providing a new tool for studying metabolic regulation and disease mechanisms.