Isolation of bronchial mucins from cystic fibrosis sputum by use of citraconic anhydride.

Citraconylation was used to solubilize cystic fibrosis sputum and to dissociate its mucus glycoproteins from extraneous proteins. The mucin fraction was isolated by precipitation with Cetavlon, and characterized in terms of amino acid and carbohydrate composition. The data suggest that, in determining the physical properties of glycoproteins of cystic fibrosis mucus, aggregation by noncovalent forces may be as important as (or more important than) disulfide bonds.