Kinetic and thermodynamic characterization of adenylyl cyclase from Euglena gracilis
| Autor: | M. Eugenia Torres-Márquez, Alicia Vega-Segura, Mohammed El-Hafidi, Ricardo Jasso-Chávez, Rafael Moreno-Sánchez |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Euglena gracilis
ved/biology.organism_classification_rank.species Biophysics Biochemistry Euglena Adenylyl cyclase chemistry.chemical_compound Adenosine Triphosphate Enzyme Stability Cyclic AMP Animals Enzyme kinetics Thermolabile Molecular Biology Growth medium biology ved/biology Cell Membrane Fatty Acids biology.organism_classification Lactic acid Kinetics chemistry Saturated fatty acid Thermodynamics Adenylyl Cyclases Signal Transduction |
| Zdroj: | Archives of Biochemistry and Biophysics. 404:48-54 |
| ISSN: | 0003-9861 |
| Popis: | Some kinetic and thermodynamic properties of the plasma membrane adenylyl cyclase (AC) from the protist Euglena gracilis were examined. The AC kinetics for Mg-ATP was hyperbolic with a Km value of 0.33–0.43 mM, whereas the inhibition exerted by 2 0 ; 5 0 dideoxyadenosine was of the mixed type with a Ki of 80–147 lM. The Vm value (0.9 or 1.8 nmol (mg protein) � 1 min � 1 ) changed, depending upon the carbon source in the growth medium (lactic acid or glutamate plus malate). Lactic acid membrane AC was slightly more thermolabile (from 28 to 40C) and showed higher activation energy (range 15–25C). With lactate, the total and saturated fatty acid percentage content in the plasma membrane was significantly greater than with glutamate plus malate, whereas the percentage content of polyunsaturated ðn � 3Þ fatty acids was lower. The data suggest that the fatty acid composition, as changed by the carbon source in the growth medium, may modulate the AC activity in Euglena. 2002 Elsevier Science (USA). All rights reserved. |
| Databáze: | OpenAIRE |
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