The primary targets of L-Azetidine-2-carboxylic acid include prolyl-tRNA synthetase, the enzyme responsible for charging tRNA with proline during protein synthesis. As a structural analog of proline, the compound is mistakenly recognized by prolyl-tRNA synthetase and incorporated into proteins in place of proline. This misincorporation disrupts protein folding and function, particularly affecting collagen synthesis, as collagen is rich in proline residues. The compound may also target pathways involved in plant defense, as it accumulates in certain plants and acts as a protective agent against herbivores. Additionally, L-Azetidine-2-carboxylic acid has been studied for its effects on collagen biosynthesis, making it relevant for research on fibrosis, wound healing, and connective tissue disorders.

In vitro, L-Azetidine-2-carboxylic acid is used to study protein folding, collagen synthesis, and the effects of proline analogs on cellular function. The compound is incorporated into proteins in place of proline, leading to the production of misfolded proteins and activation of the unfolded protein response. In cell culture models, it is used to investigate the molecular mechanisms of collagen biosynthesis and the pathogenesis of connective tissue disorders such as Ehlers-Danlos syndrome. The compound also inhibits the growth of certain cancer cells by disrupting protein synthesis. These in vitro activities support its use in cell biology, biochemistry, and fibrosis research.

In vivo, L-Azetidine-2-carboxylic acid has been studied for its antifibrotic properties, as it can inhibit collagen production in animal models of fibrosis. The compound has been shown to reduce collagen deposition in the liver, lungs, and skin in various fibrosis models, suggesting potential therapeutic applications for fibrotic diseases. It is also a plant metabolite that accumulates in certain species as a defense mechanism against herbivores. However, its use as a therapeutic agent is limited by its toxicity, as it can be incorporated into proteins throughout the body, leading to widespread protein misfolding and dysfunction.

In vitro enzyme assays for L-Azetidine-2-carboxylic acid involve studying its interaction with prolyl-tRNA synthetase. The compound is incubated with the enzyme, ATP, and tRNA at concentrations ranging from 0.1-1000 μM, and the formation of azetidine-2-carboxyl-tRNA is measured. Proline is used as a competitor to assess the specificity of the interaction. The compound’s incorporation into proteins can be studied using cell-free translation systems with labeled amino acids. All assays include appropriate controls and reference compounds.

In vitro cell-based assays for L-Azetidine-2-carboxylic acid are conducted using various cell lines, including fibroblasts, cancer cells, and plant cells. Cells are treated with compound concentrations ranging from 0.1-1000 μM for 24-72 hours. Protein synthesis and folding are assessed by Western blot, immunofluorescence, or reporter assays. Collagen production is measured using ELISA or hydroxyproline assays. Cell viability is assessed using MTT assays. The unfolded protein response is evaluated by measuring the expression of chaperone proteins. Experiments include vehicle controls and positive controls (e.g., proline).

In vivo animal studies with L-Azetidine-2-carboxylic acid are conducted in models of fibrosis, including liver fibrosis, pulmonary fibrosis, and skin fibrosis. The compound is administered via intraperitoneal or oral routes at doses ranging from 1-50 mg/kg. Collagen deposition is assessed by histological staining (e.g., Masson's trichrome) and hydroxyproline content measurement. Inflammatory markers and fibrotic gene expression are analyzed in tissues by qPCR and Western blot. Each group consists of 6-10 animals with vehicle-treated controls.

Pharmacokinetic properties of L-Azetidine-2-carboxylic acid include its absorption following oral administration and its distribution to various tissues. As a small, polar amino acid analog, it is expected to have moderate oral bioavailability. The compound is transported across cell membranes by amino acid transporters and can be incorporated into proteins throughout the body. Metabolism likely occurs through degradation pathways similar to those of proline. Elimination occurs via renal excretion. Detailed PK parameters such as half-life, Cmax, and AUC require further investigation.

Interactions
Long-term administration of carbon tetrachloride to rats can induce liver cirrhosis and increase albumin synthesis, but concurrent administration of carbon tetrachloride and L-azacyclobutane-2-carboxylic acid can reduce albumin synthesis and restore serum albumin levels to normal. L-azacyclobutane-2-carboxylic acid can significantly inhibit nitrate reductase activity induced by nitrate in radish and cauliflower leaf tissues with low L-proline content. Simultaneous injection of L-proline can reverse this inhibitory effect.
Toxicological data for L-Azetidine-2-carboxylic acid indicate that it is toxic at high doses due to its incorporation into proteins in place of proline, leading to protein misfolding and cellular dysfunction. In animal studies, administration of the compound has been associated with growth retardation, skeletal abnormalities, and organ toxicity. The compound is also a plant toxin that protects certain species from herbivory. As with all research chemicals, appropriate safety precautions should be taken during handling, and the compound should be used only for in vitro and animal research purposes.

(S)-Azacyclobutane-2-carboxylic acid is the (S)-enantiomer of azacyclobutane-2-carboxylic acid, and also the enantiomer of (R)-azacyclobutane-2-carboxylic acid. It has been reported that (S)-azacyclobutane-2-carboxylic acid exists in lily of the valley (Convallaria majalis), Clavulinopsis helvola, and other organisms with relevant data. See also: beet (partial). Mechanism of Action: Allyl glycine (0.1 mmol) inhibited the uptake of 0.1 μmol of 4,5-(3)H-labeled L-leucine (1 CUI/mmol) and U-(3)H-labeled L-proline (266 MCI/mmol) in rat brain slices. Leucine uptake was not linear with time; L-azacyclobutane-2-carboxylic acid also inhibited proline uptake. L-azacyclobutane-2-carboxylic acid effectively induced amnesia in a single avoidance conditioned reflex test in 2-day-old chicks and prevented mechanoinduced diffusion inhibition in the retinas isolated from 2-3-week-old chicks. In various protein synthesis systems, L-azacyclobutane-2-carboxylic acid can replace L-proline incorporation into proteins. Adding L-azacyclobutane-2-carboxylic acid to the culture medium of fetal rat skulls reduced intracellular free proline content by 40-70% and decreased the rate of proline incorporation into proteins and collagen by 40-70%. Changes in intracellular proline concentration (whether through alteration of extracellular proline concentration or inhibition of proline entry into the intracellular pool) may contribute to the regulation of collagen synthesis. Proline permease in Pseudomonas aeruginosa follows saturation kinetics and is specific for L-proline. L-azacyclobutane-2-carboxylic acid competitively inhibits proline uptake. It can also exchange with a pre-established intracellular pool of labeled proline.
Odontoblasts from 16-day-old mouse embryos treated with L-2-azacyclobutanecarboxylic acid (50, 100, and 200 γ) for 4 days were in late mitosis but unpolarized and did not secrete picric acid-furossing (collagen)-positive material. Odontoblasts from 18-day-old embryos treated with L-2-azacyclobutanecarboxylic acid did not contain picric acid-furossing or striated collagen fibers; pre-odontoblasts were in late mitosis but unpolarized.
L-Azetidine-2-carboxylic acid is a naturally occurring, non-proteinogenic amino acid and a four-membered ring analog of proline. It is used as a research tool to study protein folding, collagen biosynthesis, and the molecular basis of connective tissue disorders. The compound has antifibrotic properties and has been studied in animal models of fibrosis. It is also a plant metabolite that acts as a defense agent against herbivores. Not approved for clinical therapeutic use; intended for research purposes only.

C₄H₇NO₂

101.10

101.047

2133-34-8

16486

White to off-white solid powder

1.3±0.1 g/cm3

242.0±33.0 °C at 760 mmHg

206-207 ºC

100.1±25.4 °C

0.0±1.0 mmHg at 25°C

1.499

-0.83

2

3

1

7

91.7

1

C1CN[C@@H]1C(=O)O

IADUEWIQBXOCDZ-VKHMYHEASA-N

InChI=1S/C4H7NO2/c6-4(7)3-1-2-5-3/h3,5H,1-2H2,(H,6,7)/t3-/m0/s1

(2S)-azetidine-2-carboxylic acid

LAzetidine2carboxylic acid; L Azetidine 2 carboxylic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: (1). This product requires protection from light (avoid light exposure) during transportation and storage.  (2). Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O : ~100 mg/mL (~989.12 mM)
DMSO :< 1 mg/mL

Solubility in Formulation 1: 100 mg/mL (989.12 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)