6533b85cfe1ef96bd12bc979
RESEARCH PRODUCT
Retinyl ester hydrolases in retinal pigment epithelium.
Giacomo De LeoConcetta M.a. NicotraM.antonietta Di BellaAnna Maria PintaudiAlessandra PaganiniMaria Concetta GueliLeonardo Pandolfosubject
BiophysicsBiochemistrysymbols.namesakechemistry.chemical_compoundCytosolHydrolasemedicineAnimalsPigment Epithelium of EyeMolecular Biologychemistry.chemical_classificationCell NucleusRetinal pigment epitheliumChromatographybiologyChemistryCell MembraneRetinolGolgi apparatusHydrogen-Ion ConcentrationEnzyme assayCytosolKineticsmedicine.anatomical_structureEnzymeBiochemistryMicrosomesymbolsbiology.proteinCattleCarboxylic Ester HydrolasesSubcellular Fractionsdescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1991-08-01 | Archives of biochemistry and biophysics |