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Congo Red *UltraPure grade* *CAS 573-58-0*

Congo red (CR) is the sodium salt of benzidinediazo-bis-1-naphtylamine-4-sulfonic acid. CR is water soluble, yielding a red colloidal solution. It is used to stain cytoplasm and erythrocyte stain in histology. Apple-green birefringence of CR stained preparates under polarized light is indicative for the presence of amyloid fibrils. Early diagnosis and classification of amyloid deposition and differentiation from other fibrillar deposits rely on routine CR-based histochemistry. This histology assay is widely used for the characterization of in vitro amyloid fibrils. In addition, CR is also used for fluorimetric examination of amyloid fibrils. Compared to CR in bright light CR fluorescence is simple to perform and more pronounced. Although not widely used, the CR fluorimetric method for detecting amyloid is simple to use with a high specificity and sensitivity, and may be applied successfully to frozen sections.

Calculators

Common stock solution preparation

Table 1. Volume of Water needed to reconstitute specific mass of Congo Red *UltraPure grade* *CAS 573-58-0* to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM143.542 µL717.71 µL1.435 mL7.177 mL14.354 mL
5 mM28.708 µL143.542 µL287.084 µL1.435 mL2.871 mL
10 mM14.354 µL71.771 µL143.542 µL717.71 µL1.435 mL

Molarity calculator

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Spectrum

Product family

NameExcitation (nm)Emission (nm)
Amplite® Red571584
Nile Red *CAS 7385-67-3*559635
LysoBrite™ Red576596
Amylite™ Red485671

References

View all 53 references: Citation Explorer
The effects of sodium sulfate, glycosaminoglycans, and Congo red on the structure, stability, and amyloid formation of an immunoglobulin light-chain protein
Authors: McLaughlin RW, De Stigter JK, Sikkink LA, Baden EM, Ramirez-Alvarado M.
Journal: Protein Sci (2006): 1710
Acetylcholinesterase-amyloid-beta-peptide interaction: effect of Congo Red and the role of the Wnt pathway
Authors: Inestrosa NC, Alvarez A, Dinamarca MC, Perez-Acle T, Colombres M.
Journal: Curr Alzheimer Res (2005): 301
Alzheimer's beta-amyloid: insights into fibril formation and structure from Congo red binding
Authors: Inouye H, Kirschner DA.
Journal: Subcell Biochem (2005): 203
Improved detection of amyloid in fat pad aspiration: an evaluation of Congo red stain by fluorescent microscopy
Authors: Giorgadze TA, Shiina N, Baloch ZW, Tomaszewski JE, Gupta PK.
Journal: Diagn Cytopathol (2004): 300
Congo red populates partially unfolded states of an amyloidogenic protein to enhance aggregation and amyloid fibril formation
Authors: Kim YS, R and olph TW, Manning MC, Stevens FJ, Carpenter JF.
Journal: J Biol Chem (2003): 10842
Page updated on October 12, 2024

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Physical properties

Molecular weight

696.66

Solvent

Water

Spectral properties

Absorbance (nm)

195

Storage, safety and handling

Certificate of OriginDownload PDF
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22

Storage

Freeze (< -15 °C); Minimize light exposure
UNSPSC12352200

CAS

573-58-0
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