PNP-α-L-Arabinopyranoside

PNP-α-L-Arabinopyranoside (4-Nitrophenyl α-L-arabinopyranoside, CAS 1223-07-0) is a chromogenic aryl glycoside substrate specifically designed for measuring α-L-arabinopyranosidase (EC 3.2.1.55) activity in hemicellulase research and plant cell wall degradation studies. α-L-Arabinopyranosidases hydrolyze the α-glycosidic linkage, releasing yellow 4-nitrophenolate anion (ε405 nm = 18,300 M⁻¹cm⁻¹, pH >9.0) for sensitive spectrophotometric detection, enabling kinetic characterization of arabinan-degrading enzymes from fungi, bacteria, and rumen microbes. This substrate distinguishes α-L-Araf pyranose-specific hydrolases (GH93 family) from more common α-L-arabinofuranosidases (GH43, GH51, GH62), supporting selective screening in biofuel enzyme cocktails, arabinoxylan modification studies, and development of GH family-specific inhibitors for biomass saccharification.

Appearance

• White to pale yellow crystalline powder, hygroscopic.
• Soluble in water (3-8 mM), DMF/water 1:1 (>20 mM).

Source

• Koenigs-Knorr synthesis: α-L-arabinopyranosyl bromide + 4-nitrophenol, HgBr2/Ag2CO3 catalysis.
• Commercial research grade from RPI, Glycosynth, ChemicalBook suppliers.

Molecular Weight and Structure

• C11H13NO7, 271.22 g/mol; [α]D +120° ±5° (c=1, MeOH).
• α-L-Arap-(1→O)-C6H4-p-NO2; InChIKey ZKBWXYDDZTVQGQ-XLGJFGRTSA-N.

Sugar Specificity

• Selective for α-L-arabinopyranosidases (GH93); Km 0.2-0.7 mM.
• Minimal cross-reactivity with α-L-arabinofuranosidases or other glycosidases.

Biological Activity

• Hydrolysis: pNP-α-L-Arap → L-arabinose + pNP; optimal pH 4.0-5.5, 45°C.
• Specific activity 80-300 µmol pNP/min/mg for microbial α-Arap’ases.

Purity and Microbial Contamination

• ≥99% HPLC; ≥98% TLC purity; single α-anomer.
• Endotoxin-free; sterile lyophilized powder.

Identity and Quality Control

• 1H-NMR (J1,2 3.5 Hz α-anomer), HRMS (m/z 272.1 [M+H]+), optical rotation.
• Functional assay: ΔA405/min with α-L-arabinopyranosidase standard.

Shelf Life and Storage

• >2 years at -20°C in tightly closed containers; freezer/cold room.
• Protect from moisture/light; stock solutions stable 4 weeks -20°C.

Application

• α-L-Arabinopyranosidase assays in hemicellulose degradation research.
• Biofuel enzyme cocktail optimization; GH93 family screening.
• Arabinan structure-function studies; xylan modification analysis.

Key Characteristics

• Chromogenic detection (yellow pNP, ε405=18.3 mM⁻¹cm⁻¹); LOD 0.01 U/mL.
• α-L-Arap pyranose specific; thermostable; microplate compatible.

Citation Links

• https://www.chemicalbook.com/ProductDetail_EN_4-nitrophenyl-l-arabinopyranoside_2018837.htm
• https://www.rpicorp.com/products/biochemicals/other-enzymes/4-nitrophenyl-a-l-arabinopyranoside-1-g.html
• https://www.glycosynth.co.uk/det/354/p-Nitrophenyl-alpha-L-arabinopyranoside/
• https://pubchem.ncbi.nlm.nih.gov/compound/644162
• https://pmc.ncbi.nlm.nih.gov/articles/PMC106594/
• https://pubmed.ncbi.nlm.nih.gov/9614699/
• https://www.rpicorp.com/products/biochemicals/other-enzymes/4-nitrophenyl-a-l-arabinopyranoside-100-mg.html
• https://www.megazyme.com/4-nitrophenyl-alpha-l-arabinofuranoside
• https://www.bldpharm.com/products/6892-58-6.html
• http://www.chemsynlab.com/en/product/72732-54-8.html