Retinyl ester hydrolases in retinal pigment epithelium
| Autor: | Giacomo De Leo, Concetta M.A. Nicotra, M.Antonietta Di Bella, Anna Maria Pintaudi, Alessandra Paganini, Maria Concetta Gueli, Leonardo Pandolfo |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Biophysics
Biochemistry symbols.namesake chemistry.chemical_compound Cytosol Hydrolase medicine Animals Pigment Epithelium of Eye Molecular Biology chemistry.chemical_classification Cell Nucleus Retinal pigment epithelium Chromatography biology Chemistry Cell Membrane Retinol Golgi apparatus Hydrogen-Ion Concentration Enzyme assay Kinetics medicine.anatomical_structure Enzyme Microsome symbols biology.protein Cattle Carboxylic Ester Hydrolases Subcellular Fractions |
| Zdroj: | Archives of biochemistry and biophysics. 288(2) |
| ISSN: | 0003-9861 |
| Popis: | In bovine retinal pigment epithelium membranes we have found three hydrolases which were active against trans-retinyl palmitate. This was possible by assaying different subcellular fractions as a function of pH in the range 3-9. Detection of these activities has been favored by the use in the enzyme assay of Triton X-100, which has an activating effect up to a concentration of 0.03% at a detergent-protein ratio of about 1.5-3.0. Apparent kinetic parameters for the retinyl ester hydrolases have been determined after a study of the optimization of assay conditions. Vmax values for hydrolases acting at pH 4.5, 6.0, and 7.0 were, respectively, 156, 55, and 70 nmol/h/mg. To identify the subcellular site for these hydrolytic activities, assays of marker enzymes from various organelles in each subcellular preparation were carried out, demonstrating the lysosomal origin of the pH 4.5 retinyl ester hydrolase and the microsomal origin of the pH 6.0 retinyl ester hydrolase and suggesting that the pH 7.0 retinyl ester hydrolase originates from the Golgi complex. |
| Databáze: | OpenAIRE |
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