Ponceau S
Encyclopedia
Staining (biology)
Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes...
for rapid reversible detection of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
bands on nitrocellulose
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
or PVDF membranes (Western blot
Western blot
The western blot is a widely used analytical technique used to detect specific proteins in the given sample of tissue homogenate or extract. It uses gel electrophoresis to separate native proteins by 3-D structure or denatured proteins by the length of the polypeptide...
ting), as well as on cellulose acetate
Cellulose acetate
Cellulose acetate , first prepared in 1865, is the acetate ester of cellulose. Cellulose acetate is used as a film base in photography, as a component in some adhesives, and as a frame material for eyeglasses; it is also used as a synthetic fiber and in the manufacture of cigarette filters and...
membranes. A Ponceau S stain is useful because it does not appear to have a deleterious effect on the sequencing of blotted polypeptides and is therefore one method of choice for locating polypeptides on Western blots for blot-sequencing. It is also easily reversed with water washes, facilitating subsequent immunological
Immunology
Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders ; the...
detection. The stain can be completely removed from the protein bands by continued washing. Common stain formulations include 0.1% (w/v) Ponceau S in 5% acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
or 2% (w/v) Ponceau S in 30% TCA
Trichloroacetic acid
Trichloroacetic acid is an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms....
and 30% sulfosalicylic acid.