Study of the flux and transition time control coefficient profiles in a metabolic system in vitro and the effect of an external stimulator.
Control of flux and transition time was investigated with a reconstructed rabbit muscle glycolytic system in vitro as an experimental model. The results show agreement with the summation property for the Flux Control Coefficients [Kacser & Burns (1973) Symp. Soc. Exp. Biol. 27, 65-104; Heinrich & Rapoport (1974) Eur. J. Biochem. 42, 89-95]. Control of flux is almost exclusively located at the hexokinase- and phosphofructokinase-catalysed steps, whereas control of transition time is distributed more evenly between the enzymes of the system. The summation value of the Transition Time Control Coefficients is near to -1, suggesting the existence of another Summation Theorem besides that already stated for Flux Control Coefficients. Finally, we study the effect of an external stimulator of the system (fructose 2,6-bisphosphate) on the Control Coefficient profiles. The effect appears to be greater on the Transition Time Control Coefficient distribution than on the Flux Control Coefficients.
Departamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de la La Laguna, Canary Islands, Spain.
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Torres
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Souto
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Meléndez-Hevia
D000818:Animals; D005635:Fructosediphosphates / Q000378:metabolism; D006019:Glycolysis; D066298:In Vitro Techniques; D007700:Kinetics; D008956:Models, Chemical; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits
D005635:Fructosediphosphates; C027652:fructose 2,6-diphosphate