Regulation of fructose-2,6-bisphosphate content in mantle tissue of the sea mussel Mytilus galloprovincialis Lmk. Regulation of fructose-2,6-bisphosphatase activity.
Fructose-2,6-bisphosphatase (FBPase-2) from the mantle tissue of the mussel Mytilus galloprovincialis shows a hyperbolic kinetic with a Km value (0.40 mM) for its substrate, that suggest that the "in vivo" Fru-2,6-P2 concentration is not a limiting factor for activity. The enzyme possesses an optimum pH for activity between 6 and 7 units, similar to the reached in mussel mantle during physiological hypoxia. The modulation of activity by the pH, and in addition, the positive effect of ATP are in keeping with the little decrease in concentration of the Fru-2,6-P2 that occurs during the first hour of hypoxia due to the valve closure.
Vázquez-Illanes
M D
MD
Departamento de Bioquímica y Biología Molecular, Universidad de Santiago de Compostela, Facultad de Veterinaria, Lugo, Spain.
Ventura
F
F
Ramos-Martínez
J I
JI
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D049872:Bivalvia / Q000378:metabolism*; D015687:Cell Hypoxia; D004789:Enzyme Activation; D005635:Fructosediphosphates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*
D005635:Fructosediphosphates; C027652:fructose 2,6-diphosphate; D000255:Adenosine Triphosphate; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases