Isolation and Characterization of Sulfated Glycoproteins from the Brush Border Fraction and the Soluble Fraction of Rabbit Small Intestine

Abstract

The brush border fraction (Fr. P₂) and the calcium chloride (10mM)-soluble fraction (Fr. S) were separated from the small intestinal mucosa of rabbit. Sulfated glycoproteins, P-SGP and S-SGP, were then purified from Fr. P₂ and Fr. S by zone electrophoresis and gel filtration, respectively. P-SGP and S-SGP were both electrophoretically homogeneous, although their mobilities differed from each other. P-SGP and S-SGP contained 61.8 and 35.3% protein, 31.8 and 55.0% carbohydrate, and 1.1 and 2.7% sulfate, respectively. The major constituent sugars in P-SGP and S-SGP were galactose and glucosamine, while mannose, sialic acid, and L-fucose were minor components. In addition, galactosamine was a major sugar in S-SGP, but a minor one in P-SGP. The major amino acids of the protein moiety of P-SGP were glutamic acid, aspartic acid, glycine, and alanine, while those of S-SGP were threonine, proline, glutamic acid, aspartic acid, serine, and glycine.