The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.
% SDS-PAGE. ab73640 is purified by proprietary chromatographic techniques. Purity is greater than 95.0% as determined by RP-HPLC and SDS-PAGE.
Additional notesReconstitution to filaments:
Performed by mixing equimolar amounts of cytokeratins of type I and type II at concentrations of approx. 0.5 mg/ml, both dissolved in 9.5 M urea buffer (see above). Protofilaments and filament complexes are obtained by dialyzing the resulting polypeptide solution stepwise to a concentration of 4 M urea and then to low salt condition (50 mM NaCI, 2 mM dithiothreitol, 10 mM Tris-HCI, pH 7.4). For immunization purposes, the solution can be further dialyzed against PBS (phosphate buffered saline, e.g. Dulbecco's PBS).
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Preparation and Storage
Stability and Storage
Shipped at 4°C. Upon delivery aliquot and store at -20°C. Avoid repeated freeze / thaw cycles.
ReconstitutionReconstitute in sterile 18MO-cm H2O not less than 100µg/ml, which can then be further diluted to other aqueous solutions.
keratin 20, type I
keratin 21, rat, homolog of
Keratin type I cytoskeletal 20
type I cytoskeletal 20
FunctionPlays a significant role in maintaining keratin filament organization in intestinal epithelia. When phosphorylated, plays a role in the secretion of mucin in the small intestine.
Tissue specificityExpressed predominantly in the intestinal epithelium. Expressed in luminal cells of colonic mucosa. Also expressed in the Merkel cells of keratinized oral mucosa; specifically at the tips of some rete ridges of the gingival mucosa, in the basal layer of the palatal mucosa and in the taste buds of lingual mucosa.
Sequence similaritiesBelongs to the intermediate filament family.
Developmental stageFirst detected at embryonic week 8 in individual 'converted' simple epithelial cells of the developing intestinal mucosa. In later fetal stages, synthesis extends over most goblet cells and a variable number of villus enterocytes. In the developing gastric and intestinal mucosa, expressed in all enterocytes and goblet cells as well as certain 'low-differentiated' columnar cells, whereas the neuroendocrine and Paneth cells are negative.
Post-translational modificationsHyperphosphorylation at Ser-13 occurs during the early stages of apoptosis but becomes less prominent during the later stages. Phosphorylation at Ser-13 also increases in response to stress brought on by cell injury. Proteolytically cleaved by caspases during apoptosis. Cleavage occurs at Asp-228.