Glucose-6-phosphate dehydrogenase in small intestine of rabbit: biochemical properties and subcellular localization
| Autor: | Gianfranca Aluigi, Manuela Malatesta, Giancarlo Gazzanelli, Enrica Biagiotti, Paolino Ninfali |
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| Rok vydání: | 2001 |
| Předmět: |
Male
Histology Brunner Glands Biology Glucosephosphate Dehydrogenase digestive system chemistry.chemical_compound symbols.namesake hemic and lymphatic diseases parasitic diseases Intestine Small medicine Glucose-6-phosphate dehydrogenase Animals Intestinal Mucosa chemistry.chemical_classification Chromatography Endoplasmic reticulum Phosphogluconate Dehydrogenase Cell Biology General Medicine Golgi apparatus Subcellular localization Molecular biology Immunohistochemistry Small intestine Epithelium medicine.anatomical_structure Enzyme Enterocytes chemistry Cytoplasm symbols Electrophoresis Polyacrylamide Gel Rabbits Dialysis |
| Zdroj: | Scopus-Elsevier |
| Popis: | Summary Biochemical properties and cellular and subcellular distribution patterns of glucose-6-phosphate dehydrogenase (G6PD) were investigated in small intestine of rabbits. The specific activity of G6PD in fresh homogenates of small intestine was 19 ± 9 IU/g protein. This value did not change significantly after dialysis. The kinetic and electrophoretic properties of the partially purified enzyme were similar to those found in other rabbit tissues. Enzyme histochemical analysis of G6PD activity using the tetrazolium salt method showed high activity in epithelial cells of villi and crypts of LieberkIhn. The activity in acinar cells of Brunner's glands was lower than that in epithelium, whereas cells of the muscularis externa showed a very low activity. Immunohistochemical analysis showed that the amounts of G6PD protein were lower in the epithelium than in Brunner's glands and muscularis externa. The differences between distribution patterns of activity and protein of G6PD may reflect the presence of inactive enzyme molecules in Brunner's glands and muscularis externa or posttranslational activation of G6PD in epithelium. Electron microscopic immunocytochemical analysis performed with gold-labelled antibodies showed the presence of G6PD protein throughout the cytoplasm and at smooth endoplasmic reticulum in enterocytes. In Paneth cells and cells of Brunner's glands, G6PD was found in the cytoplasm, at rough endoplasmic reticulum and Golgi complex. Immunolabelling was not found in mitochondria or nuclei. Our findings show that G6PD is heterogeneously distributed in cells of the small intestine and that the enzyme is associated with rough and smooth endoplasmic reticulum to support synthetic functions in these compartments by NADPH production. |
| Databáze: | OpenAIRE |
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