Kinetic properties, solubilization, and molecular characterization of Mucor rouxii adenylate cyclase

Particulate cell fractions of mycelium of Mucor rouxii contain adenylate cyclase activity which can be partially solubilized by 0.5 m KCl. Homogenates prepared in the presence of Lubrol PX or KCl exhibit two- to threefold more activity compared to homogenates prepared in the absence of detergent or...

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Autor principal: Cantore de Ezcurra, María Leonor
Publicado: 1982
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00039861_v219_n1_p1_Cantore
http://hdl.handle.net/20.500.12110/paper_00039861_v219_n1_p1_Cantore
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Sumario:Particulate cell fractions of mycelium of Mucor rouxii contain adenylate cyclase activity which can be partially solubilized by 0.5 m KCl. Homogenates prepared in the presence of Lubrol PX or KCl exhibit two- to threefold more activity compared to homogenates prepared in the absence of detergent or salt. The membrane-bound enzyme prepared in the presence of 2% Lubrol PX was studied in detail. The kinetic properties of this adenylate cyclase were as expected for an allosteric enzyme with the ATP · Mn2- complex as substrate and free Mn2+ ions as activator. Unchelated ATP inhibits the reaction by competing with the substrate. The KCl-solubilized enzyme was partially purified by ion-exchange chromatography, ammonium sulfate precipitation, and gel filtration. Molecular parameters of the solubilized enzyme are: Stokes radius, 8.6 nm; S20,w, 13S; Mr 510,000; and frictional ratio, 1.60. © 1982.