4‑MU‑α‑L‑Arabinopyranoside

4‑MU‑α‑L‑Arabinopyranoside (CAS 69414‑26‑2) is a synthetic α‑L‑arabinosidase‑specific fluorogenic substrate in which a 4‑methylumbelliferyl aglycone is linked via an α‑glycosidic bond to the anomeric carbon of α‑L‑arabinopyranose. When hydrolyzed by α‑L‑arabinosidases (e.g., α‑arabinofuranosidases or α‑arabinopyranosidases depending on the enzyme), the glycosidic bond is cleaved to release 4‑methylumbelliferone (4‑MU) and α‑L‑arabinose. The released 4‑MU exhibits strong blue fluorescence under UV excitation, allowing highly sensitive, continuous monitoring of enzyme activity in microplate‑based assays. 4‑MU‑α‑L‑Arabinopyranoside is widely used in enzymology to characterize α‑arabinosidase activity in microbial, plant, and fungal systems, to study enzyme‑substrate specificity among arabinosyl‑glycosides, and to quantify activity in kinetic experiments (Km, Vmax) and inhibitor‑screening assays. The compound is supplied as a high‑purity, water‑or slightly DMSO‑soluble powder, and is suitable for glycobiology, plant‑polysaccharide, and microbial‑metabolism studies, including work on arabinoxylans and hemicellulose‑degrading systems. Its high sensitivity and compatibility with standard fluorometers and microplate readers make it a preferred tool for α‑arabinosidase‑activity measurements.

Appearance

• White to almost white crystalline or amorphous powder.
• Forms a slightly cloudy or clear solution in water when heated or sonicated; develops intense blue fluorescence only after enzymatic hydrolysis.

Source / synthesis

• Synthetically prepared by glycosylation of 4‑methylumbelliferol with α‑L‑arabinopyranose or a protected α‑L‑arabinoside, followed by deprotection and crystallization from water or aqueous alcohols.
• Commercially supplied by biochemical‑reagent and specialty‑sugar‑chemistry vendors (e.g., Sigma‑Aldrich, Chem‑Impex, GlycoSynth, ChemSynlab, Chinese‑based suppliers) as a research‑grade α‑arabinosidase substrate.

Molecular weight and structure

• Molecular formula: C15H16O7C15​H16​O7​.
• Molecular weight: 308.28 g/mol.
• Structure: 4‑methylumbelliferyl‑α‑L‑arabinopyranoside, with an α‑glycosidic linkage between the aromatic 4‑methylumbelliferyl group and the anomeric oxygen of the L‑arabinose ring in the pyranose form.

Sugar specificity

• Specifically hydrolyzed by α‑L‑arabinosidases and α‑L‑arabinoside‑cleaving glycosidases, including α‑arabinofuranosidase‑type enzymes depending on the linkage and system.
• Frequently used in fluorogenic panels to distinguish α‑arabinosidase activity from other glycosidase activities (e.g., β‑xylosidase, α‑glucosidase) in plant and microbial extracts.

Biological activity

• Serves as a fluorogenic reporter whose rate of 4‑MU release under defined pH and temperature conditions reflects α‑L‑arabinosidase activity.
• Enables determination of kinetic parameters (Km, Vmax), inhibitor‑IC₅₀, and comparative activity profiling of different arabinosidases involved in plant‑polysaccharide and hemicellulose breakdown.

Purity and microbial contamination

• Typically supplied at ≥97–99% purity (e.g., “≥99% HPLC” or “≥99%”) as indicated by supplier data sheets and product‑specification labels.
• Described as a non‑sterile, research‑grade solid suitable for use in standard enzymatic assays under clean‑laboratory conditions.

Identity and quality control

• Identity inferred from molecular formula, molecular weight, UV‑Vis/fluorescence spectra, and predicted pKa (~12.8–13), with 4‑methylumbelliferone‑type chromophore.
• Quality‑control includes checks for appearance, solubility, melting point or literature‑predicted boiling point, and performance in a defined α‑arabinosidase or α‑arabinofuranosidase activity assay (e.g., in microplate‑based enzyme panels).

Shelf life and storage

• Shelf life is generally 12–24 months when stored at 2–8 °C, sealed in a dry, light‑protected container, often recommended for slightly hygroscopic material.
• Aqueous working solutions are best prepared fresh or stored at 4 °C for short periods; long‑term storage, UV exposure, and elevated temperature should be avoided to prevent photodegradation or nonspecific hydrolysis.

Application

• Fluorimetric assay of α‑L‑arabinosidase and α‑arabinofuranosidase activity in microbial, plant, and fungal systems.
• Enzyme‑kinetic studies, inhibitor‑screening, and substrate‑specificity profiling for arabinoxylan‑ and hemicellulose‑degrading glycosidases.
• Use in plant‑biology, food‑science, and biotechnology research where carbohydrate‑binding proteins (lectins) or glycosidase activity in complex polysaccharide degradation is under investigation.

Key characteristics

• Fluorogenic readout based on 4‑methylumbelliferone release, enabling highly sensitive, microplate‑compatible detection of α‑L‑arabinosidase activity.
• Defined α‑L‑arabinopyranoside linkage providing selectivity for α‑arabinosidases and related arabinosyl‑cleaving enzymes.
• High‑purity, crystalline powder with a known molecular formula and weight, suitable for quantitative enzyme assays and standardized protocols.

Citations

• Sigma‑Aldrich – 4‑Methylumbelliferyl‑α‑L‑arabinopyranoside (≥99% HPLC, CAS 69414‑26‑2, MF C₁₅H₁₆O₇, MW 308.28): https://www.sigmaaldrich.com/US/en/product/sigma/m3167
• Chem‑Impex – 4‑Methylumbelliferyl‑α‑L‑arabinopyranoside product page (CAS 69414‑26‑2, key substrate for α‑arabinofuranosidase assays): https://www.chemimpex.com/products/21216
• ChemSynlab – 4‑Methylumbelliferyl‑α‑L‑arabinopyranoside (CAS 69414‑26‑2, English‑language product listing): http://chemsynlab.com/en/product/69414-26-2.html
• ChemSynlab (Chinese) – 4‑Methylumbelliferyl‑α‑L‑arabinopyranoside technical note and biological‑properties description: http://chemsynlab.com/cn/product/69414-26-2.html
• GeneSeqTools – 4‑MU‑α‑L‑Arabinopyranoside news‑detail page (fluorescence‑based substrate overview, CAS 69414‑26‑2): http://www.geneseqtools.cn/en/news‑detail_cid_29_id_147.html
• GlycoSynth – 4‑Methylumbelliferyl‑α‑L‑arabinopyranoside Safety Data Sheet (CAS 69414‑26‑2, product code 44018): https://www.glycosynth.co.uk/userdata/files/44018‑SDS.pdf
• ChemicalBook – 4‑methylumbelliferyl‑α‑L‑arabinopyranoside general‑properties listing (CAS 69414‑26‑2, physical and storage‑temp data): https://www.chemicalbook.com/Manufacturers‑india/4‑methylumbelliferyl‑alpha‑l‑arabinopyranoside.htm
• Sinochem‑Nanjing – 4‑Methylumbelliferyl‑α‑L‑arabinopyranoside product page (CAS 69414‑26‑2, biochemical‑research applications): https://www.sinochem‑nanjing.com/products/other‑chemicals/4‑methylumbelliferyl‑alpha‑l‑arabinopyranoside‑cas‑69414‑26‑2.html
• PMC article on α‑L‑arabinofuranosidases using 4‑MU‑α‑L‑arabinofuranoside‑type substrates (general method‑context for 4‑MU‑Arabinoside‑use): https://pmc.ncbi.nlm.nih.gov/articles/PMC6414367/
• General glycosidase‑substrate catalog (4‑MU‑α‑L‑Arabinopyranoside and related 4‑MU‑glycosides overview): https://www.chemicalbook.com/ (search for “69414‑26‑2”).