5-Amino-1MQ: The NNMT Inhibitor Explained

5-Amino-1MQ is a small molecule, not a peptide: it is 5-amino-1-methylquinolinium, a quaternary methylquinolinium cation with the formula C10H11N2+ and a molecular weight of 159.21 g/mol, usually supplied as the iodide salt (C10H11IN2, 286.11 g/mol). It is studied as an inhibitor of nicotinamide N-methyltransferase (NNMT), the cytosolic enzyme that transfers a methyl group from S-adenosylmethionine to nicotinamide. It is investigational: no product containing it is approved by any regulator, and the published record is laboratory and rodent work.

Because most of this catalog is peptides, the first point is worth restating. 5-Amino-1MQ has no amino acids and no peptide bonds. It is a single aromatic heterocycle with a methylated ring nitrogen and an amine substituent, closer in kind to a laboratory enzyme probe than to a synthetic peptide. That changes how it is weighed, dissolved, analyzed and stored, and this profile covers each in turn.

Identity at a glance

The values below come from the PubChem records for the cation (CID 950107) and for the iodide salt (CID 66522933).

Two features of the structure explain most of its behavior. The quinolinium nitrogen carries a methyl group and a fixed positive charge, so the molecule is a permanent cation at every pH rather than a base that can be titrated. And that cation has to be paired with a counterion, which in commerce is almost always iodide. Both numbers in the table matter for that reason: the same sample can be described as 159.21 or 286.11 g/mol depending on whether the cation or the salt is being counted, a ratio of about 1.80.

The N-methylated aromatic nitrogen is also what links the molecule to its target. The product of the NNMT reaction, 1-methylnicotinamide, is likewise a small N-methylated aromatic cation, and the methylquinolinium series was developed as a set of compounds built around that motif.

The enzyme: NNMT

Nicotinamide N-methyltransferase is a cytosolic, S-adenosylmethionine-dependent methyltransferase. The human enzyme is catalogued in UniProt as P40261, a single chain of 264 amino acids, classified under EC 2.1.1.1. It catalyzes one reaction: the transfer of a methyl group from S-adenosylmethionine (SAM) to the ring nitrogen of nicotinamide, producing 1-methylnicotinamide (1-MNA) and S-adenosylhomocysteine.

That single reaction sits at a junction of two metabolic pools. Nicotinamide is a precursor for NAD+ through the salvage pathway, so methylating it diverts material away from NAD+ regeneration. SAM is the cell's general methyl donor, used for histone and DNA methylation and consumed in polyamine synthesis. Inhibiting the enzyme therefore has arithmetic consequences for both pools, which is the reason it attracted attention as a metabolic target.

The 2014 Nature paper by Kraus and colleagues is the study that put NNMT on that map. Using DNA array analysis, they found Nnmt to be the most strongly reciprocally regulated gene when comparing white adipose tissue from mice with adipose-specific Glut4 knockout against adipose-specific Glut4 overexpression. They then knocked the gene down with antisense oligonucleotides in mouse adipose tissue and liver and reported increased tissue SAM and NAD+ levels, changes in polyamine flux through ornithine decarboxylase and spermidine-spermine N1-acetyltransferase, altered histone H3 lysine 4 methylation, and increased oxygen consumption in adipocytes that depended on those polyamine enzymes. Their framing of NNMT was as a regulator of histone methylation, polyamine flux and NAD+-dependent SIRT1 signaling.

What was reported for the methylquinolinium series

Neelakantan and colleagues published the characterization of this compound series in Biochemical Pharmacology in 2018. Four findings from that paper describe what 5-amino-1MQ and its analogs do at the molecular level:

• Permeability. Methylquinolinium scaffolds carrying primary amine substitutions showed high membrane permeability in a parallel artificial membrane assay and in Caco-2 cell monolayers. This is not trivial for a permanently charged cation, and it was one of the design goals of the series.
• Selectivity. The compounds did not inhibit structurally related SAM-dependent methyltransferases or enzymes of the NAD+ salvage pathway in the assays tested, which is what distinguishes an enzyme-selective probe from a general methyltransferase poison.
• Target engagement in cells. In cultured adipocytes, the inhibitors lowered intracellular 1-MNA, the direct product of the NNMT reaction, and raised intracellular NAD+ and SAM. Lower product plus higher substrate-side cofactor is the signature expected if the enzyme is genuinely being inhibited inside the cell rather than only in a tube.
• Lipogenesis. The same cultured adipocyte work reported suppression of lipogenesis.

The paper also reported an in-vivo arm in mice fed a high-fat diet. This profile does not restate those animal findings; the point for a laboratory is that the cellular observations above are the ones that define the compound as an NNMT inhibitor, and the paper is open access through PubMed Central for anyone who needs the assay conditions.

What the published record does not settle is the binding mode in atomic detail for 5-amino-1MQ specifically, or the degree to which the compound's cellular effects can be attributed to NNMT alone. Selectivity data against a panel is evidence, not proof of a single mechanism, and a permanently charged small molecule that accumulates in cells can have targets no one has assayed yet.

Research models

The systems named in the two primary sources above are: cultured adipocytes for metabolite and lipogenesis measurements; Caco-2 monolayers and parallel artificial membrane assays for permeability; recombinant enzyme assays against NNMT and against related methyltransferases and NAD+ salvage enzymes for selectivity; mouse white adipose tissue and liver with antisense knockdown of Nnmt; and mice on a high-fat diet. Work on NNMT itself extends well beyond metabolism, into tumor biology and other fields, but this profile stays with the two papers that establish the compound and its target.

Regulatory status

5-Amino-1MQ is not an approved drug in the United States or, so far as published sources show, anywhere else. There is no approved product containing it, and no published Phase 1 or later human trial for the compound in the sources cited here.

It also does not appear by name in the 2026 World Anti-Doping Agency Prohibited List. That absence is not a permission: the list's S0 class covers any pharmacological substance not addressed elsewhere on the list and with no current approval by a governmental regulatory authority for human use, and it is prohibited at all times. Whether a given unapproved compound falls under S0 is a determination for anti-doping authorities, not for a supplier.

Material from Anhydrolabs is supplied for in-vitro laboratory research only, and is not for human or veterinary diagnosis, treatment, or consumption.

Laboratory handling and storage

5-Amino-1MQ is supplied as a lyophilized powder in vacuum-sealed vials, available on the 5-Amino-1MQ catalog page and in 10-vial kits. Being a small molecule and a salt, it differs in several ways from the peptides described elsewhere on this blog, including MOTS-c and AOD9604.

Know which mass you are using. A stock solution calculated from 159.21 g/mol when the vial contains the iodide salt will be off by a factor of about 1.80. Read the certificate of analysis for the salt form and the stated net content before calculating a concentration in mg/mL or molarity.

Light and iodide. Iodide salts are light-sensitive, and oxidation of iodide to iodine shows as a yellow or brown tint in the solid or in solution. Keep vials in the dark, minimize headspace, and treat discoloration as a reason to check identity rather than to proceed.

Moisture. Quaternary ammonium salts are often hygroscopic. Store the vial sealed with desiccant, and let it equilibrate to room temperature before opening so water does not condense onto the solid. The general principles are the same as for peptide powders, covered in how to store peptides and on the storage and handling page.

Weighing. At 159.21 g/mol for the cation, this is a light molecule by the standards of a peptide catalog, so a small absolute error in net content translates into a large relative error in molarity. Weigh by difference where the experiment demands accuracy, and prefer dissolving a whole vial of known net content over subsampling a powder.

Solubility. A permanently charged, low-molecular-weight cation is generally water-soluble, and aqueous stocks are the usual starting point; dimethyl sulfoxide is the common alternative for cell work, with the solvent fraction kept low and matched in controls. Confirm against the lot's certificate rather than assuming.

Analytics. Small molecules are checked differently from peptides. Identity comes from NMR and from LC-MS showing the cation at a monoisotopic mass near 159.09, with no peptide-style charge-state envelope to interpret. Purity is reported by HPLC-UV as the area of the principal peak. The counterion is quantified separately, typically by ion chromatography or elemental analysis, and a residual solvent figure is worth looking for. The HPLC principles are the same ones described in how HPLC measures peptide purity, even though the analyte is not a peptide; for that contrast, see what peptides are.