caa a22 4500 477117066 CHVBK 20180405111625.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF01875571 doi (NATIONALLICENCE)springer-10.1007/BF01875571 Characterization of mevalonate metabolism in the sea bass ( Dicentrarchus labrax L) liver [Elektronische Daten] [A. Estévez, A. Delgado, P. Hortelano, M. Alejandre] The activities of mevalonate kinase, mevalonate 5-phosphate kinase and mevalonate 5-pyrophosphate decarboxylase, were examined in sea bass (Dicentrarchus labrax L) liver. The activities of the three enzymes were studiedin vitro in relation to the influence of protein content, time of incubation, pH, temperature, mevalonate, ATP and Mg++ concentration. Protein content in the assay medium affected the three enzymes differently. Mevalonate kinase, mevalonate 5-phosphate kinase, and mevalonate 5-pyrophosphate decarboxylase activities were linear up to 0.2, 0.4 and 0.8 mg protein, respectively. With respect to the time course studies, the enzymes also behaved differently. Mevalonate kinase activity increased over forty minutes, reaching a plateau thereafter, while mevalonate 5-phosphate kinase and decarboxylase increased over the entire assay period. All the three enzymes showed a maximum in activity at pH 7.5. The effect of reaction temperature showed that phosphorylation increased to maximum around 35°C for mevalonate kinase and 30°C for mevalonate 5-phosphate kinase while decarboxylation rates remained constant well until 30°C temperature decreasing afterwards. The enzymes behaved differently as a function of mevalonate concentration. Mevalonate 5-phosphate formed was maximal when the initial mevalonate concentration was 272 μM, whereas mevalonate 5-pyrophosphate and CO2 were formed maximally at mevalonate concentrations of 136 μM and 68μM, respectively. Optimal ATP concentration in the medium was 3 mM for decarboxylase and 6 mM for kinases, and Mg++ requirements varied from 4 mM for decarboxylase to 6 mM for kinases. Kugler Publication, 1996 sea-bass nationallicence cholesterol nationallicence mevalonate kinase nationallicence mevalonate 5-phosphate kinase nationallicence mevalonate 5-pyrophosphate decarboxylase nationallicence Estévez A. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut Delgado A. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut Hortelano P. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut Alejandre M. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut Fish Physiology and Biochemistry Kluwer Academic Publishers 15/3(1996-06-01), 205-211 0920-1742 15:3<205 1996 15 10695 https://doi.org/10.1007/BF01875571 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01875571 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Estévez A. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut NATIONALLICENCE 700 1- Delgado A. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut NATIONALLICENCE 700 1- Hortelano P. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut NATIONALLICENCE 700 1- Alejandre M. Department of Biochemistry and Molecular Biology, University of Granada, 18001, Granada, Spain aut NATIONALLICENCE 773 0- Fish Physiology and Biochemistry Kluwer Academic Publishers 15/3(1996-06-01), 205-211 0920-1742 15:3<205 1996 15 10695 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer