title: Inhibition by gangliosides of Bacillus cereus phospholipase C activity against monolayers, micelles and bilayer vesicles.
abstract: The effect of complex glycosphingolipids (gangliosides) on the activity of phospholipase C from Bacillus cereus was studied using lipid monolayers, mixed micelles and small unilamellar vesicles containing phosphatidylcholine as substrate. In all artificial membrane systems assayed, gangliosides exhibit qualitatively similar inhibitory properties. Gangliosides decrease the enzyme activity irrespective of the aggregation structure in which the substrate is offered to B. cereus phospholipase C, and they do not affect the adsorption process of the enzyme. The modulatory effect of gangliosides occurs at the level of the interface, affecting both the maximum rate of catalysis of the enzyme already adsorbed and the availability of the substrate in a suitable organization for enzyme catalysis to take place.
authors.affiliation: Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas-CONICET, Universidad Nacional de Córdoba, Argentina.
authors.forename: J J
authors.initials: JJ
authors.lastname: Daniele
authors.forename: B
authors.initials: B
authors.lastname: Maggio
authors.forename: I D
authors.initials: ID
authors.lastname: Bianco
authors.forename: F M
authors.initials: FM
authors.lastname: Goñi
authors.forename: A
authors.initials: A
authors.lastname: Alonso
authors.forename: G D
authors.initials: GD
authors.lastname: Fidelio
mesh_terms: D001409:Bacillus cereus / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005732:Gangliosides / Q000494:pharmacology*; D008051:Lipid Bilayers; D008823:Micelles; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D005732:Gangliosides; D008051:Lipid Bilayers; D008823:Micelles; D010738:Type C Phospholipases