LaMont JT, Ventola AS. Purification and composition of colonic epithelial mucin.
BIOCHIMICA ET BIOPHYSICA ACTA 1980;
626:234-43. [PMID:
7459381 DOI:
10.1016/0005-2795(80)90214-7]
[Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Colonic mucin was purified from homogenized scrapings of rat colonic epithelial cells using gel filtration and ion-exchange chromatography. High molecular weight water-soluble mucin was separated from low molecular weight proteins by gel exclusion chromatography on Sepharose 4B, and was further separated into two major mucin fractions and several non-mucin fractions on DEAE-cellulose. Fraction IV, the major mucin, was a sulphated glycoprotein with 62% carbohydrate by weight, and high concentrations of serine and threonine. A more acidic mucin, fraction V, had similar composition. Approx. 85% of the sialic acid of fractions IV and V were removed after incubation with Clostridium perfringens neuraminidase. Blood group A but not group H activity was present in fractions III, IV, and V. Ultracentrifugation experiments showed that fraction IV migrated as a single peak, whereas fraction V contained two components. Our study indicates that colonic mucin consists of at least two closely related acidic high molecular weight glycoproteins which can be separated from non-mucin contaminants by ion-exchange chromatography.
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