Abstract
Age-specific changes in glycosylation of rat intestinal L-Ph were analyzed using enzyme immunoprecipitaled from microvillus membranes (MVM) of suckling, weaning, and adult rats, and carbohydrate moieties were examined by lectin affinity binding, metabolic labeling, and neuraminidase treatment. Lectin binding indicated the presence of N-linked and O-linked oligosaccharide chains containing mannosa and galactose throughout development. An age dependent shift in sialic acid and fucose was demonstrated during the period of weaning; no fucose was detectable in L-Ph until after 20 days of age, while sialic acid was reducad in adult L-Ph. The presence of sialic acid in suckling, and fucose in adult, intestine was confirmed by metabolic labeling with appropriate radioactive precursors. SDS-PAGE analysis of immunoprecipitated L-Ph from proximal and mid email intestine demonstrated two bands of approximately 220 kDa and 130 kDa in all age groups. In the distal part of the adult small intestine, L-Ph appeared as two bands of similar size to those found in the proximal and mid portions. In contrast, during the suckling and weaning period, these distal bands were approximately 225 and 135 kDa. [35S]-methionine labeling and fluorography of newborn intestine confirmed these observations. This size difference was virtually eliminated by neuraminidase treatment. These data indicate that the core structure of MVM L-Ph, consisting of both N-linked and O-linked oligosaccharides, remains constant during development, although terminal sugars shift from predominantly sialic acid during the suckling period to fucose in adulthood. This alteration in glycosylation of the protein occurs in a different pattern from the post-weaning decline in L-Ph specific activity. Consequently, age depandent changes in glycosylation cannot account for the decrease in L-Ph specific activity observed during development.
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Rings, E., Buller, H., Pajkrt, D. et al. GLYCOSYLATION OF LACTASE-PHLORIZIN HYDROLASE (L-Ph) IN RAT SMALL INTESTINE DURING DEVELOPMENT. Pediatr Res 27, 544 (1990). https://doi.org/10.1203/00006450-199005000-00116
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DOI: https://doi.org/10.1203/00006450-199005000-00116