Interaction of calmodulin with muscle phosphofructokinase. Changes of the aggregation state, conformation and catalytic activity of the enzyme.
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Interaction of calmodulin with muscle phosphofructokinase. Changes of the aggregation state, conformation and catalytic activity of the enzyme. / Mayr, Georg W.
in: EUR J BIOCHEM, Jahrgang 143, Nr. 3, 3, 1984, S. 513-520.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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TY - JOUR
T1 - Interaction of calmodulin with muscle phosphofructokinase. Changes of the aggregation state, conformation and catalytic activity of the enzyme.
AU - Mayr, Georg W.
PY - 1984
Y1 - 1984
N2 - Phosphofructokinase from muscle has been shown to be a calmodulin-binding protein [Mayr, G.W. and Heilmeyer, L.M.G., Jr (1983) FEBS Lett. 159, 51-57]. Details of the influence of calmodulin on the aggregation state, the conformation and the catalytic properties of phosphofructokinase have been studied by enzymatic and light-scattering analyses. Calmodulin acts as a Ca2+-dependent hysteretic inhibitor of the highly active enzyme. At least one mole of calmodulin binds to each protomer of the enzyme, induces a shift from the highly active tetrameric towards an inactive dimeric state and slowly changes the conformation of the dimers. Dissociation of calmodulin from conformationally changed dimers by removal of Ca2+ stops the inactivation. Without a significant regain of catalytic activity large polymers are rapidly formed. For a reactivation of the inactivated enzyme, calmodulin has to remain associated and the incubation conditions must be changed in a way to allow for a back isomerization and reassociation of dimers. The isomerization reaction is promoted by Mg . ATP, the reassociation reaction most effectively by fructose bisphosphate. A model for the calmodulin-phosphofructokinase interaction is proposed.
AB - Phosphofructokinase from muscle has been shown to be a calmodulin-binding protein [Mayr, G.W. and Heilmeyer, L.M.G., Jr (1983) FEBS Lett. 159, 51-57]. Details of the influence of calmodulin on the aggregation state, the conformation and the catalytic properties of phosphofructokinase have been studied by enzymatic and light-scattering analyses. Calmodulin acts as a Ca2+-dependent hysteretic inhibitor of the highly active enzyme. At least one mole of calmodulin binds to each protomer of the enzyme, induces a shift from the highly active tetrameric towards an inactive dimeric state and slowly changes the conformation of the dimers. Dissociation of calmodulin from conformationally changed dimers by removal of Ca2+ stops the inactivation. Without a significant regain of catalytic activity large polymers are rapidly formed. For a reactivation of the inactivated enzyme, calmodulin has to remain associated and the incubation conditions must be changed in a way to allow for a back isomerization and reassociation of dimers. The isomerization reaction is promoted by Mg . ATP, the reassociation reaction most effectively by fructose bisphosphate. A model for the calmodulin-phosphofructokinase interaction is proposed.
M3 - SCORING: Zeitschriftenaufsatz
VL - 143
SP - 513
EP - 520
IS - 3
M1 - 3
ER -
