5-Amino-1MQ: Mechanism of Action

1. Primary Target — NNMT Enzyme

The molecular target of 5-Amino 1MQ is the cytosolic enzyme nicotinamide N-methyltransferase (NNMT), a metabolic regulator highly expressed in adipose tissue, liver, and skeletal muscle — particularly in obesity and type 2 diabetes. [2]

Binding Mechanism: 5-Amino 1MQ is a substrate-competitive inhibitor. It competes with nicotinamide (NAM) for the active binding site of NNMT, preventing the enzyme from catalyzing the transfer of a methyl group from SAM to NAM. This blockade prevents formation of 1-methylnicotinamide (1-MNA) and S-adenosyl-L-homocysteine (SAH). [3]

Potency:

• IC₅₀: ~1.0–1.2 µM for NNMT inhibition [1]
• EC₅₀: 2.3 ± 1.1 µM (reduction of intracellular 1-MNA levels) [1]
• Lipogenesis Inhibition: 30 µM reduced lipogenesis by 50%; 60 µM by 70%

2. Downstream Cascade A — NAD+ Salvage and SIRT1 Activation

NNMT normally acts as a “sink” for nicotinamide, permanently removing it from the NAD+ salvage pathway by methylating it into 1-MNA (which is then excreted). By inhibiting NNMT, 5-Amino 1MQ preserves the intracellular NAM pool, shunting it back into the NAD+ salvage pathway and significantly increasing intracellular NAD+ levels. [4]

Elevated NAD+ acts as a co-substrate for sirtuins, specifically activating SIRT1 — often called the “longevity gene.” SIRT1 activation drives increased mitochondrial biogenesis and metabolic rate. [8]

3. Downstream Cascade B — Methionine-SAM Cycle and Epigenetic Regulation

NNMT consumes SAM (the universal methyl donor) during NAM methylation. 5-Amino 1MQ prevents this consumption, increasing intracellular SAM levels and reducing SAH (a methylation inhibitor). This alters the cell’s epigenetic methylation potential, influencing histone and DNA methylation states that regulate gene expression for adipogenesis and metabolism. [4] [9]

4. Downstream Cascade C — Exercise Mimicry (Muscle-Specific)

In skeletal muscle, 5-Amino 1MQ triggers unique signaling: [10]

• Ribosomal Biogenesis: Upregulates proteins involved in ribosomal RNA biogenesis and aminoacyl-tRNA ligase activity, mimicking the protein translation signaling normally induced by exercise.
• Transsulfuration Pathway: Uniquely upregulates the transsulfuration pathway (via cystathionine β-synthase), enhancing protection against reactive oxygen species (ROS) via glutathione synthesis.
• AMPK Activation: Shifts the metabolome of sedentary muscle toward an exercised state via increased AMP, driving AMPK activation — a critical energy sensor promoting muscle hypertrophy and protein translation.

5. Receptor Selectivity

5-Amino 1MQ demonstrates high selectivity for NNMT, avoiding off-target effects: [3]

• Does NOT inhibit structurally related SAM-dependent methyltransferases: DNMT1, PRMT3, COMT
• Does NOT inhibit NAD+ pathway enzymes: NAMPT, SIRT1

This confirms that NAD+ and SAM increases result solely from preventing their degradation by NNMT, not from interfering with their synthesis or utilization enzymes.

6. Cellular and Tissue-Level Effects

Adipose Tissue (White Fat):

• Suppresses lipogenesis (fat creation) in adipocytes [1]
• Reduces white adipocyte size by >30% and WAT mass by ~35% [2]
• Produces a unique metabolomic signature (increased ketogenic amino acids)
• No alteration in food intake [2]

Skeletal Muscle:

• Activates senescent muscle stem cells (MuSCs), promoting proliferation and myofiber repair [11]
• Nearly 2-fold increase in myofiber cross-sectional area; ~70% increase in peak torque
• Sustained running capacity without fatigue taper [10]

Liver:

• Reverses hepatic steatosis (fatty liver) and normalizes ALT/AST [12]
• Reduces total plasma cholesterol by ~30% [2]

7. Pharmacokinetics

Parameter	Rat (Oral)	Rat (IV)
Oral Bioavailability	38.4%	—
Half-Life (T½)	6.9 ± 1.2 h	3.8 ± 1.1 h
Cmax	2,252 ng/mL	—
Membrane Permeability	High (passive + active transport)
Tissue Distribution	Adipose, muscle, liver; no 24h accumulation in heart/kidney/brain

Source: Awosemo/Neelakantan et al., J. Pharm. Biomed. Anal., 2021 [7]