可作为发光底物检测β-葡萄糖苷酶(GUS)基因。
比旋光度：-90° - -86°
溶解性：溶于二甲基甲酰胺(DMF)，参考浓度10mg/ml。
Product Number:：CS1803
CAS Number: 114162-64-0
Storage Temperature: −20℃
Product Description :
Appearance: White crystalline powder
Molecular formula: C20H26BrClN2O7
Molecular Weight: 521.80
Synonyms: 5-Bromo-4-chloro- 3-indolyl-β-D-glucuronide acid, cyclohexylammonium salt; X-GlcA; BC-Indicator; X-glucuronide
The gus operon in Escherichia coli is composed of three genes. The first gene, uidA(gusA), encodes the enzyme β-glucuronidase (GUS). GusB encodes a glucuronide permease. The function of the gusC gene product is unknown. 5-bromo-4-chloro-3-indolyl-β-D-glucuronide (X-GlcA, X-Gluc) has been shown to be a good substrate for GUS, yielding a dark-blue insoluble cleavage product. The reaction (see Figure) initially yields a monomeric intermediate, which rapidly oxidizes to form the dimer, dichlorodibromoindigo (ClBr-indigo).
Figure 1.
Hydrolysis of X-GlcA by b-Glucuronidase
The intense coloration and insolubility of ClBr-indigo is ideal for use as an indicator of GUS activity in situ. It has been used as an indicator of E. coli contamination in various food items and as an agent in urinary tract infections. The gusA gene has been used as an indicator of transfection and as a reporter gene for the function of regulatory elements in plants.
If using a known strain of E. coli as a positive control for GUS activity, it is important to realize that K-12 strains of E. coli contain a defective permease. Even though X-GlcA is an excellent inducer of uidA in E. coli, K-12 strains require much higher levels of X-GlcA than wild-type strains. With a defective permease, high extracellular levels of X-GlcA are needed to develop sufficient intracellular levels so that uidA is adequately induced. In addition, once uidA is induced and GUS activity is high, high extracellular levels of X-GlcA are also needed to develop sufficient intracellular levels to react and to yield a dark coloration.
Preparation Instructions
Prepare a 40 mg/ml stock solution of X-Gluc in N, N-dimethylformamide (DMF) or dimethylsulfoxide (DMSO).
Storage/Stability:
Store the product at –20℃. When stored at –20℃, the Product is good as long as color remains white.
Procedures:
As an indicator for the presence of E. coli in natural materials
Prepare LB Agar. Cool to 55℃. Add 250μl of a 40 mg/ml stock solution of X-Gluc in DMSO to 100 ml of LB agar and mix gently to dissolve.
The final concentration of X-GlcA in the medium will be 100 μg/ml. Pour plates and allow to cool for a few hours or overnight. Streak one plate with a uidA+ strain of E. coli (ATCC 11303) and a second plate with a uidA– strain of E. coli (GMS407). Incubate the plates at 37℃ for 24 hours.
As a substrate for the GUS reporter system to study plant gene expression
Please refer to published procedures.
Precautions and Disclaimer:
For Laboratory Use Only. Not for drug, household or other uses.
