Native mucin-like complexes were obtained from both pig gallbladder bile and pig gallbladder wall mucus by precipitation, centrifugation, and gel permeation chromatography. Crude preparations by either dialysis (native mucus from bile, and native gallbladder wall mucus) or by precipitation (crude total bile mucus, and lipomucoid) were purified by gel permeation chromatography on Sephacryl S-300HR and Sephacryl S-500HR (Pharmacia). The elution profiles obtained with a reversibly denaturing and

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... tergentcontaining eluent showed the same pattern for all samples, although the amounts of the four main fractions differed somewhat. The excluded fraction with the highest carbohydrate portion had an apparent M r > 10 7 . This fraction and the following included lipomucoid (in physiological solution tightly bound to fraction I), and an eluent-insoluble mucus portion from all samples were characterized by determination of the protein concentration, carbohydrates, sialic acids, and lipids, using standard methods. Sugar analysis was performed by gas-liquid chromatography. Human gallbladder bile was subjected to the same procedures of mucus precipitation and separation. Human gallbladder bile mucus showed identical behaviour to that of pig gallbladder bile mucus, and showed a very similar elution pattern in gel chromatography.