What Is 5-Amino-1MQ? Structure and NNMT Chemistry

5-Amino-1MQ often gets grouped with peptides. But it isn't a peptide at all. It's a small, charged ring molecule.

At our small Michigan shop, we like to explain what a compound actually is. So this post sticks to the chemistry: the structure, the enzyme it was made to study, and how labs check a sample.

What Is 5-Amino-1MQ?

5-Amino-1MQ is short for 5-amino-1-methylquinolinium. PubChem lists its formal name as 1-methylquinolin-1-ium-5-amine [1].

It is a small molecule, not a peptide. A peptide is a chain of amino acids. 5-Amino-1MQ has none. It is one fused ring system with two small groups attached.

PubChem lists these basics for the molecule [1]:

• Formula: C10H11N2+ (note the plus sign)
• Molecular weight: 159.21 g/mol
• Exact mass: 159.0922 Da
• Other identifiers: CAS number 685079-15-6 and ChEMBL ID CHEMBL4116828

Breaking Down the Name

The name describes the structure, one piece at a time.

Quinoline: the ring system

Quinoline is two six-membered rings joined side by side. One is a benzene ring. The other contains a nitrogen atom.

"1-Methyl" and "-ium": the charged nitrogen

A methyl group (CH3) sits on the ring nitrogen, at position 1. That gives the nitrogen four bonds and a permanent positive charge.

The "-ium" ending signals that charge. Chemists call this a quaternary nitrogen.

"5-Amino": the extra group

An amino group (-NH2) sits at position 5, on the benzene side of the ring system [1].

Why It Usually Comes as a Salt

A molecule with a permanent positive charge can't exist as a solid by itself. It needs a negatively charged partner, called a counterion.

One common form is the iodide salt. As reference chemistry, PubChem lists 5-amino-1-methylquinolinium iodide as C10H11IN2, with a molecular weight of 286.11 g/mol [2].

This matters when you read paperwork:

• The charged molecule alone: about 159 g/mol
• The iodide salt: about 286 g/mol

Always check which form a document describes.

Where 5-Amino-1MQ Came From

The enzyme: NNMT

5-Amino-1MQ was designed to study an enzyme called nicotinamide N-methyltransferase, or NNMT.

NNMT adds a methyl group to nicotinamide (one form of vitamin B3) and to other pyridine-type molecules [3][4]. The methyl group comes from a common cell molecule called S-adenosyl-L-methionine, or SAM [5].

A Mayo Clinic team cloned the liver form of NNMT in 1994. They reported a protein 264 amino acids long, weighing about 29.6 kDa [3].

One interesting detail: NNMT can also add a methyl group to quinoline itself. The product is 1-methylquinolinium, which glows under the right light. A University of Texas group used that glow to build a real-time NNMT test [5].

Building a better inhibitor

In 2017, researchers at the University of Texas Medical Branch in Galveston and UT San Antonio tested a family of methylated ring compounds against NNMT [6].

Quinoliniums stood out. Several blocked the enzyme at low concentrations in lab tests [6]. Their IC50 values were around 1 µM. (IC50 is the concentration needed to cut enzyme activity in half. Lower means stronger.)

A 2018 follow-up paper focused on 5-amino-1MQ [7]. In that work:

• Strength: 5-amino-1MQ had an NNMT IC50 of about 1.2 µM. The parent compound, 1-methylquinolinium, was about 12.1 µM [7].
• Membrane passage: Plain 1-methylquinolinium did not pass through artificial membranes. Adding the amino group changed that. 5-amino-1MQ showed high permeability in artificial-membrane and Caco-2 cell-layer tests [7].
• Selectivity: At the concentrations tested, it did not meaningfully block several related enzymes, including COMT, DNMT1, PRMT3, NAMPT and SIRT1 [7].

That selectivity is why it became a common lab tool for studying NNMT. A 2017 review covers the wider research interest in NNMT, including how it uses methyl donors [4].

How Labs Check Identity and Purity

Identity: mass spectrometry

Mass spectrometry measures a molecule's mass. 5-Amino-1MQ already carries its own charge. So a lab would look for a signal near 159.09, the exact mass PubChem lists for the charged molecule [1].

The counterion, such as iodide, does not appear in that signal.

Purity: HPLC

High-performance liquid chromatography (HPLC) separates a sample into its parts. A purity result tells you how much of the material is the target compound.

When you read any lab report, check that the identity result and the purity result refer to the same lot.

Our standard

Every batch must meet a 98% minimum purity before it's sold. Lab documentation is available to verified purchasers.

Storage

Like most research compounds, 5-amino-1MQ material should stay sealed, cold, dry and away from light. For the basics, see our guide to lyophilized peptide storage.

Want more compound chemistry? Read What Is Glutathione?, What Is GHK-Cu? and What Is KPV?

FAQ

Is 5-Amino-1MQ a peptide?

No. It is a small quinolinium molecule with no amino acids. It is often listed alongside peptides, but its chemistry is different [1].

What is the molecular weight of 5-Amino-1MQ?

The charged molecule is 159.21 g/mol [1]. The iodide salt is 286.11 g/mol [2]. Check which form a document lists.

What does "1MQ" stand for?

1-methylquinolinium. "5-amino" means an amino group sits at position 5 of the ring system [1].

What enzyme is 5-Amino-1MQ associated with?

Nicotinamide N-methyltransferase (NNMT). Researchers developed it as a selective, membrane-permeable NNMT inhibitor for lab studies [6][7].

For laboratory research use only. Not for human or veterinary use.

Sources

1. PubChem: 5-Amino-1-methylquinolinium (CID 950107)
2. PubChem: 5-Amino-1-methylquinolinium iodide (CID 66522933)
3. Aksoy S, Szumlanski CL, Weinshilboum RM. Human liver nicotinamide N-methyltransferase: cDNA cloning, expression, and biochemical characterization. Journal of Biological Chemistry, 1994;269(20):14835-40. PubMed 8182091
4. Pissios P. Nicotinamide N-Methyltransferase: More Than a Vitamin B3 Clearance Enzyme. Trends in Endocrinology and Metabolism, 2017;28(5):340-353. doi:10.1016/j.tem.2017.02.004
5. Neelakantan H, Vance V, Wang HL, McHardy SF, Watowich SJ. Noncoupled Fluorescent Assay for Direct Real-Time Monitoring of Nicotinamide N-Methyltransferase Activity. Biochemistry, 2017;56(6):824-832. doi:10.1021/acs.biochem.6b01215
6. Neelakantan H, Wang HY, Vance V, Hommel JD, McHardy SF, Watowich SJ. Structure-Activity Relationship for Small Molecule Inhibitors of Nicotinamide N-Methyltransferase. Journal of Medicinal Chemistry, 2017;60(12):5015-5028. doi:10.1021/acs.jmedchem.7b00389
7. Neelakantan H, Vance V, Wetzel MD, et al. Biochemical Pharmacology, 2018;147:141-152. doi:10.1016/j.bcp.2017.11.007