Title of article :
Kinetic and thermodynamic characterization of adenylyl cyclase from Euglena gracilis
Author/Authors :
Jasso-Chلvez، نويسنده , , Ricardo and Vega-Segura، نويسنده , , Alicia and El-Hafidi، نويسنده , , Mohammed and Moreno-Sلnchez، نويسنده , , Rafael and Eugenia Torres-Mلrquez، نويسنده , , M، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2002
Abstract :
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′,5′-dideoxyadenosine was of the mixed type with a Ki of 80–147 μM. 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 40 °C) and showed higher activation energy (range 15–25 °C). 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 (n−3) 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.
Keywords :
fatty acids , Protist , Signal transduction , adenylyl cyclase , CAMP , enzyme kinetics , Euglena gracilis
Journal title :
Archives of Biochemistry and Biophysics
Journal title :
Archives of Biochemistry and Biophysics