Chlorophenol red-β-D-galactopyranoside  (Synonyms: CPRG)

Chlorophenol red-β-D-galactopyranoside (CPRG) is an efficient and sensitive chromogenic substrate for β-galactosidase (HY-P2869), widely used in colorimetric assays. Chlorophenol red-β-D-galactopyranoside itself appears pale yellow. When it is specifically hydrolyzed by β-galactosidase, it releases chlorophenol red. The released chlorophenol red turns purple-red under alkaline or neutral pH conditions. This color change from yellow to red can be quantitatively detected at wavelengths of 540-572 nm using visible spectrophotometry^[1][2].

Guide (The following is our recommended solution. This solution is merely a guideline and should be modified according to your specific needs.)
1. Reagents and Materials
Substrate stock solution: CPRG, dissolved in sterile double-distilled water, prepare a 16.5 mM stock solution. Filter sterilization (0.2 μm), store at 4°C in the dark.
Detection buffer: 100 mM phosphate buffer, pH 6.8. Add 1 mM MgCl? and 50 mM 2-Mercaptoethanol (HY-Y0326) (to stabilize enzyme activity and prevent oxidation).
Enzyme/sample: Samples containing β-galactosidase (such as cell lysate, induced yeast/bacterial culture supernatant, pure enzyme, etc.).
Positive control: Known active β-galactosidase.
Negative control: Detection buffer without enzyme.
Instrument: 96-well plate, microplate reader (with 540-572 nm filter), constant temperature incubator.
2. Experimental Procedures
2.1 Preparation of Working Solution: Add the CPRG stock solution to the detection buffer, and prepare a working solution with a final concentration of 2.5 mM CPRG.
2.2 Sample Addition: In a 96-well plate, add 50 μL of enzyme/sample solution and 50 μL of CPRG working solution to each well. (The total volume is 100 μL. Set duplicate wells and include positive control wells and negative control wells.)
2.3 Incubation and Reading: Immediately place the microplate in a 37°C constant temperature incubator. Start the kinetic reading program. Read the absorbance every 1-2 minutes at a wavelength of 572 nm for 30-60 minutes.
2.4 Data Analysis: Plot a reaction curve with time on the x-axis and absorbance (A572) on the y-axis. Usually, the linear growth period is selected to calculate the rate of change in absorbance over time (ΔA/min). This rate is proportional to the activity of β-galactosidase in the sample.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

585.41

C₂₅H₂₂Cl₂O₁₀S

99792-79-7

Solid

Brown to reddish brown

O=S1(OC(C2=CC(Cl)=C(C=C2)O[C@@H]3O[C@@H]([C@@H]([C@@H]([C@H]3O)O)O)CO)(C4=CC(Cl)=C(C=C4)O)C5=CC=CC=C51)=O

Room temperature in continental US; may vary elsewhere.

-20°C, protect from light

*In solvent : -80°C, 6 months; -20°C, 1 month (protect from light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (protect from light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

* Note: If you choose water as the stock solution, please dilute it to the working solution, then filter and sterilize it with a 0.22 μm filter before use.

• [1]. Sicard C, et al. A rapid and sensitive fluorimetric β-galactosidase assay for coliform detection using chlorophenol red-β-D-galactopyranoside. Anal Bioanal Chem. 2014 Sep;406(22):5395-403.  [Content Brief]

  [2]. Els Vanderperren, et al. Oestrogenic activity of CPRG (chlorophenol red-β-D-galactopyranoside), a β-galactosidase substrate commonly used in recombinant yeast oestrogenic assays. Biomarkers. 2001;6(5):375-80.  [Content Brief]