Localization of lipoprotein unesterified cholesterol in nondenaturing gradient gels with filipin.

A method is described for the staining of lipoprotein unesterified cholesterol in nondenaturing polyacrylamide gradient gels with the fluorescent polyene antibiotic, filipin. The sensitivity of the filipin stain was comparable to that of oil red O and Coomassie R250 in terms of the amount of lipoprotein applied. Filipin successfully stained discoidal complexes of apoA-I-phosphatidylcholine-cholesterol, which in turn were stained poorly with oil red O. The potential for the identification of unesterified cholesterol-enriched lipoprotein subclasses was demonstrated.