5-Amino-1MQ

5-Amino-1MQ (5-amino-1-methylquinolinium) is a selective, membrane-permeable small molecule inhibitor of nicotinamide N-methyltransferase (NNMT) — a cytosolic enzyme that catalyses the transfer of a methyl group from S-adenosylmethionine (SAM) to nicotinamide, generating 1-methylnicotinamide (1-MNA) and S-adenosylhomocysteine (SAH). NNMT is expressed at particularly high levels in white adipose tissue, liver, and skeletal muscle, making it directly relevant to metabolic disease research.

The primary research rationale for NNMT inhibition centres on two interconnected metabolic consequences. First, blocking NNMT prevents nicotinamide from being methylated and diverted away from the NAD+ salvage pathway. Nicotinamide that is not consumed by NNMT becomes available to NAMPT (nicotinamide phosphoribosyltransferase), the rate-limiting enzyme of the salvage pathway, which converts it to NMN and ultimately to NAD+. This redirection elevates intracellular NAD+ concentrations and increases downstream sirtuin activity — particularly SIRT1 and SIRT3, which require NAD+ as a co-substrate for their protein deacylase activity.

Second, NNMT inhibition preserves the SAM/SAH ratio. SAM is the universal methyl donor for over 200 cellular methyltransferase reactions including DNA methylation (DNMT1, DNMT3a/b), histone methylation (EZH2, G9a, PRMT5), and RNA methylation. SAH — the product generated when NNMT consumes SAM — is a potent product inhibitor of all SAM-dependent methyltransferases. By blocking NNMT, 5-Amino-1MQ prevents SAH accumulation and maintains methyltransferase activity throughout the cell, with potential epigenetic consequences including maintained histone methylation marks and DNA methylation patterns.

5-Amino-1MQ was characterised as a selective NNMT inhibitor by Neelakantan et al. (Biochemical Pharmacology, 2018). The compound's membrane permeability (enabled by its lipophilic quinolinium core) allows cell entry without transporters, and its selectivity for NNMT over related methyltransferases has been assessed in published competition assays. Target engagement is confirmed by measuring 1-MNA production in conditioned medium or cell lysates by LC-MS/MS — a direct, quantitative readout of NNMT activity in treated versus untreated cells.

In 3T3-L1 adipocyte research models, the most commonly used system for NNMT biology, 5-Amino-1MQ treatment at 1-100 microM produces measurable changes in lipid droplet content, adipogenic gene expression (PPAR-gamma, FABP4, adiponectin), oxygen consumption rate (measured by Seahorse XF analysis), and the NAD+/NADH ratio. Controls should include NNMT siRNA knockdown (to confirm effects are NNMT-dependent) and NMN or NR supplementation (to compare NNMT inhibition-driven NAD+ elevation with direct NAD+ precursor approaches).

The epigenetic research dimension of 5-Amino-1MQ is examined using ChIP-seq for H3K4me3 (active transcription mark) and H3K27me3 (silencing mark), and bisulphite sequencing of CpG methylation sites in genomic regions affected by NNMT overexpression. Research connecting NNMT to insulin resistance uses phospho-Akt (Ser473) and phospho-IRS-1 (Tyr612) as readouts of insulin signalling fidelity in adipocyte and hepatocyte models.

5-Amino-1MQ also serves as a complementary research tool alongside NAD+ (direct supplementation), NMN (salvage pathway substrate), and SLU-PP-322 (ERR agonist for mitochondrial biogenesis) in studies examining the NAD+-sirtuin-mitochondria axis. The NNMT-NAMPT competition for nicotinamide creates a pharmacological node where 5-Amino-1MQ and direct NAD+ precursors can be compared for their relative contributions to NAD+ pool expansion.

Molecular formula: C10H10N2. MW: 174.20 g/mol. CAS: 36993-88-1. Appearance: yellow to orange powder reflecting quinolinium chromophore absorption. Supplied at greater than or equal to 98% purity by HPLC. Reconstitute in DMSO at 100mM stock, dilute in aqueous media to working concentrations. Store at -20°C, protected from light. For laboratory and analytical research purposes only.