Biosynthesis of a fucose-containing glycopeptide from rat small intestine in normal and vitamin A-deficient conditions.

The number of goblet cells in the small intestine decreased in the vitamin A-deficient rat. Incorporation of W-D-glucosamine into a fucose-containing glycopeptide declined markedly. Ultracentrifugation of this glycopeptide in Hz0 gave only a single component, with a sedimentation value of 3.6 S, whereas, in 0.1 M phosphate buffer (pH 7.5) two components appeared, with much higher sedimentation constants (6.2 S and 7.2 S). The glycopeptide was found to contain glucosamine, galactose, fucose, and sialic acid in the molar ratios of 3 :3: 1:0.25, respectively. Synthesis of the fucose-containing glycopeptide in vifro, using uridine-diphosphate-N-acetyl-D-gh.tcosamine-l-’4C and 3H-serine, showed a 2to 3-fold decrease in the incorporation of the labels by rough endoplasmic reticulum prepared from vitamin A-deficient animals as compared with normal animals.