A distinct d-fructose transport system in isolated brush border membrane
| Autor: | Ulrich Hopfer, Kristine Sigrist-Nelson |
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| Rok vydání: | 1974 |
| Předmět: |
Time Factors
Brush border Phlorizin Biophysics Biological Transport Active Fructose Tritium Biochemistry Epithelium chemistry.chemical_compound Isomerism Intestine Small Animals Mannitol Carbon Radioisotopes Intestinal Mucosa Fucose Sodium digestive oral and skin physiology Glucose transporter Galactose Cell Biology Fructose transport Sorbose Rats Glucose Phlorhizin Membrane chemistry Chromatography Thin Layer Thiocyanates |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 367:247-254 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(74)90047-9 |
| Popis: | The transport of d -fructose in isolated rat intestinal epithelial brush border membranes was studied. 1. 1.|The rates of d -fructose entry appeared to be slower than d -glucose but faster than either l -glucose or d -mannitol. 2. 2.| d -Fructose uptake, measured after 45 s of incubation, was linear up to and saturable above 200 mM while d -mannitol uptake, with identical incubation conditions, continued to be linear. 3. 3.|Isolated membranes were preloaded with unlabeled d -glucose or d -fructose. The uptake of labeled d -fructose was stimulated in the d -fructose-preloaded membranes and unaffected in the d -glucose-preloaded membranes. Conversely, d -glucose transport was enhanced in the d -glucose-preloaded membranes and unaltered in the d -fructose-preloaded membranes. 4. 4.|No influence of Na + or phlorizin on d -fructose uptake could be demonstrated. In the same experiment d -glucose was stimulated approximately 3-fold by Na + , and strongly inhibited by phlorizin. 5. 5.|None of the sugars tested ( d -glucose, d -galactose, l -sorbose or d -galatose), at 100 : 1 test inhibitor to substrate ratio decreased d -fructose transport. Using the same membrane preparation, d -glucose transport was inhibited 75% by d -galactose. These results suggest the existence of a distinct transport system for d -fructose, separate from that of d -glucose. |
| Databáze: | OpenAIRE |
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