Electron microscopic cytochemical localization of?-hydroxyacid oxidase in rat kidney cortex
| Autor: | Sabine Angermüller, C. Leupold, Kurt Zaar, H. D. Fahimi |
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| Rok vydání: | 1986 |
| Předmět: |
Male
Kidney Cortex Histology Hydroxybutyric acid Microbodies Substrate Specificity chemistry.chemical_compound medicine Animals Molecular Biology chemistry.chemical_classification Oxidase test Kidney Histocytochemistry Rats Inbred Strains Cell Biology General Medicine Peroxisome Mandelic acid Rats Staining Alcohol Oxidoreductases Microscopy Electron Medical Laboratory Technology Vibratome Enzyme medicine.anatomical_structure chemistry Biochemistry Anatomy General Agricultural and Biological Sciences |
| Zdroj: | Histochemistry. 85:411-418 |
| ISSN: | 1432-119X 0301-5564 |
| DOI: | 10.1007/bf00982671 |
| Popis: | The substrate specificity of alpha-hydroxyacid oxidase in the rat kidney has been investigated cytochemically by the cerium technique and biochemically with a luminometric assay applied to isolated renal peroxisomes. Rat kidneys were fixed by perfusion via the abdominal aorta with a low concentration (0.25%) of glutaraldehyde. Vibratome sections were incubated for 60 min at 37 degrees C in a medium containing 3 mM CeCl3, 100 mM NaN3 and 5 mM of an alpha-hydroxyacid in 0.1 M Pipes or 0.1 M Tris-maleate buffer both adjusted to pH 7.8. Ten aliphatic alpha-hydroxyacids with chain lengths between 2 and 8 carbon atoms and two aromatic substrates were tested. The alpha-hydroxyacid oxidase in the kidney exhibited a markedly different substrate specificity than the corresponding enzyme in the liver. Thus glycolate gave a negative reaction while two aromatic substrates, mandelic acid and phenyllactic acid, stained prominently. With aliphatic substrates a stronger reaction was obtained in Pipes than in the Tris-maleate buffered incubation media. The best reaction in the kidney was obtained with hydroxybutyric acid. These cytochemical findings were confirmed by the luminometric determination of the oxidase activity in isolated purified peroxisome fractions. By electron microscopy the electron dense reaction product of cerium perhydroxide was found in the matrix of peroxisomes in the proximal tubules. The intensity of reaction varied markedly in neighbouring epithelial cells but also in different peroxisomes within the same cell. Thus heavily stained particles were seen next to lightly reacted ones. These observations establish the substrate specificity of alpha-hydroxyacid oxidase in the rat kidney and demonstrate the marked heterogeneity in the staining of renal peroxisomes for this enzyme. |
| Databáze: | OpenAIRE |
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