Screening Reagents

In order to observe activity inside certain cells, a screening reagent is used. These agents produce insoluble precipitates of various colors in screening for the presence of certain enzymatic activity. Screening reagents of high quality produce the best results, and using GoldBio branded reagents allows for the clearest results.
Showing 21-25 of 25 items.

TMB, free base

Catalog ID Size Pricing
TMBF10 10 g $ 80.00
TMBF25 25 g $ 160.00
TMBF50 50 g $ 289.00
TMBF100 100 g $ 513.00
TMBF250 250 g $ 1,200.00

Description

TMB is an excellent colorimetric substrate for detection of horseradish peroxidase labeled probes and is used with peroxidase and peroxidase-coupled systems, particularly in ELISA techniques. It produces a soluble end product, which is blue in color and can be read spectrophotometrically. TMB has also been used in the quantitative determination of hemoglobin and in cytochemical staining for peroxidase. TMB is a hepatitis B antigen.

Product Specifications

Catalog ID TMBF
CAS # 54827-17-7
MW 240.35 g/mol
Grade MOLECULAR BIOLOGY GRADE
Storage/Handling Store desiccated at 4°C. Protect from light.
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Packs & Pricing
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TMBF10 2-3 Weeks 10 g $ 80.00
TMBF25 2-3 Weeks 25 g $ 160.00
TMBF50 2-3 Weeks 50 g $ 289.00
TMBF100 2-3 Weeks 100 g $ 513.00
TMBF250 2-3 Weeks 250 g $ 1,200.00

X-Gal

Catalog ID Size Pricing
X4281C 1 g $ 59.00
X4281C10 10 g $ 289.00

Description

5-Bromo-4-chloro-3-indolyl β-D-galactopyranoside is most commonly known as X-Gal. X-gal is a histochemical substrate for β-galactosidase which cleaves X-Gal to yield an insoluble blue precipitate.

X-Gal is a mainstay in molecular biology cloning applications in which it is used to detect the activity of β-galactosidase. X-Gal is used to detect the insertion of foreign DNA into the lacZ region of a plasmid DNA. Insertion of DNA into the lacZ region results in the loss of β-galactosidase activity. Bacteria cells that retain active β-galactosidase will result in characteristic blue colonies. Successful disruption of the lacZα gene disrupts the α-complementation of the β-galactosidase gene and the precipitate does not form, resulting in white colonies.

Many other applications also use X-Gal as a substrate to detect β-galactosidase activity. These include β-galactosidase -antibody linked immunoassays and immunohistochemistry, coliphage detection based on β-galactosidase induction and the detection of micrometastasis formation during tumor progession.

Product Specifications

Catalog ID X4281
Name(s) X-Gal;
5-Bromo-4-chloro-3-indoxyl-beta-D-galactopyranoside
CAS # 7240-90-6
Grade MOLECULAR BIOLOGY GRADE
Formula C14H15BrClNO6
MW 408.63 g/mol
Biological Activity Blue color with Lambda, pUC, and M13
PubChem Chemical ID 619018
Storage/Handling Store at -20°C. Protect from light.
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Packs & Pricing
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X4281C In stock 1 g $ 59.00
X4281C10 In stock 10 g $ 289.00

X-gluc (CHX salt)

Catalog ID Size Pricing
G1281C 100 mg $ 59.00
G1281C1 1 g $ 205.00
G1281C2 2 x 1 g $ 395.00
G1281C3 3 x 1 g $ 555.00
G1281C4 4 x 1 g $ 665.00
G1281C5 5 g $ 765.00

Description

X-Gluc is a chromogenic substrate for beta-glucuronidase (GUS) which is encoded by the gusA (uid A) gene, a widely used reporter gene. Glucuronidase cleaves X-Gluc to produce colorless glucuronic acid and an intense blue precipitate. X-Gluc is often used in GUS staining of plant cells and tissue and in infections caused by E. coli.

Product Specifications

Catalog ID G1281
CAS # 114162-64-0
MW 521.79 g/mol
Grade MOLECULAR BIOLOGY GRADE
Storage/Handling Store desiccated at -20°C. Protect from light.
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Packs & Pricing
,
G1281C In stock 100 mg $ 59.00
G1281C1 In stock 1 g $ 205.00
G1281C2 In stock 2 x 1 g $ 395.00
G1281C3 In stock 3 x 1 g $ 555.00
G1281C4 In stock 4 x 1 g $ 665.00
G1281C5 In stock 5 g $ 765.00

X-pal

Catalog ID Size Pricing
B-470-100 100 mg $ 113.00
B-470-250 250 mg $ 219.00
B-470-500 500 mg $ 388.00
B-470-1 1 g $ 713.00

Description

X-pal is an off white to light brownish powder that is used as a chromogenic substrate for carboxylesterase. X-pal yields a blue precipitate when cleaved.

Product Specifications

Catalog ID B-470
CAS # 341972-98-3
MW 484.91 g/mol
Grade MOLECULAR BIOLOGY GRADE
Storage/Handling Store at -20°C. Protect from light.
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Packs & Pricing
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B-470-100 2-3 Weeks 100 mg $ 113.00
B-470-250 2-3 Weeks 250 mg $ 219.00
B-470-500 2-3 Weeks 500 mg $ 388.00
B-470-1 2-3 Weeks 1 g $ 713.00

X-α-Gal

Catalog ID Size Pricing
XA250 250 mg $ 115.00
XA500 500 mg $ 195.00
XA1 1 g $ 295.00
XA5 5 g $ 1,175.00
XA10 10 g $ 1,995.00

Description

X-α-Gal is a chromogenic substrate for α-galactosidase, yielding a blue precipitate. X-α-Gal is used for detecting two-hybrid interactions directly on the culture media. This substrate eliminates the need for β-galactosidase liquid and filter-lift assays in two-hybrid analysis.
Used for species differentiation within the family Enterobacteriaceae and differentiation of Bifidobacteria species from Lactobacilli species.

Product Specifications

Catalog ID XA
CAS # 107021-38-5
MW 408.64 g/mol
Grade MOLECULAR BIOLOGY GRADE
Storage/Handling Store at -20°C. Protect from light.
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Packs & Pricing
,
XA250 In stock 250 mg $ 115.00
XA500 In stock 500 mg $ 195.00
XA1 In stock 1 g $ 295.00
XA5 In stock 5 g $ 1,175.00
XA10 In stock 10 g $ 1,995.00

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