Skip to product information
Request a Quote
ONPG (o-Nitrophenyl β-D-galactopyranoside) | Chromogenic Substrate for β-Galactosidase Assays
$29.00 AUD
Documentation
Quantitative Enzyme Substrate
ONPG (o-Nitrophenyl β-D-galactopyranoside)
The standard chromogenic substrate for quantitative β-galactosidase assays. Hydrolysis releases o-nitrophenol, providing a rapid, measurable yellow color change for kinetic and coliform analysis.
CAS: 369-07-3 Cat No: ASE-904 λmax: 420 nm
Product Overview
ONPG is a color-neutral compound that serves as a highly sensitive indicator for lacZ gene expression. Unlike indolyl substrates (like X-Gal) which produce insoluble precipitates, ONPG yields a water-soluble yellow product, making it the preferred choice for:
- Enzyme Kinetics: Precise determination of Vmax and Km for β-galactosidase.
- Coliform Testing: Rapid detection and quantification of coliform bacteria in water and food samples.
- Molecular Biology: Measuring the strength of promoters and enhancers in reporter gene assays.
The Detection Principle
ONPG (Colorless) + β-Galactosidase + H2O
↓
Galactose + o-Nitrophenol (Yellow)
*The reaction is typically stopped with sodium carbonate (Na2CO3) to shift the pH and maximize the yellow absorbance at 420 nm.
Specifications
Molecular Formula C₁₂H₁₅NO₈
Molecular Weight 301.25 g/mol
Storage Temperature -20°C (Deep Freeze)
Solubility Water or Buffer
Purity ≥98% (HPLC)
Safety Note: Handle with standard lab PPE. Review SDS for complete handling instructions.
AuSaMicS Life Science | Product ASE-904