Isolation and characterization of sulfated glycoproteins from the brush border fraction and the soluble fraction of rabbit small intestine.

The brush border fraction (Fr. P2) and the calcium chloride (10 mM)-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.% protein, 31.8 and 55.0% carbohdyrate, 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.