Localization of kappa-casein on thin sections of casein micelles by the gold method.
The ultrastructural location of kappa-casein in bovine casein micelles was investigated by the protein A-gold method. Casein micelles, fixed in glutaraldehyde, were embedded at low temperature to enhance immunocytochemical marking of thin sections. kappa-Casein was found distributed throughout the micelles of all sizes with a higher concentration in the smaller micelles. No peripheral location of kappa-casein was observed, even in the larger micelles. These results do not agree with "coat-core" structures proposed for casein micelles. However they favor models where kappa-casein is distributed uniformly throughout the micelles.
D000818:Animals; D002364:Caseins / Q000032:analysis*; D002417:Cattle; D003102:Colloids; D006020:Glycopeptides / Q000032:analysis*; D006046:Gold; D006651:Histocytochemistry; D008823:Micelles; D008854:Microscopy, Electron; D013205:Staphylococcal Protein A
D002364:Caseins; D003102:Colloids; D006020:Glycopeptides; D008823:Micelles; D013205:Staphylococcal Protein A; C020251:kappa-casein glycomacropeptide; D006046:Gold