Mode of Action of Cholera Toxin: Stabilization of Catecholamine-Sensitive Adenylate Cyclase in Turkey Erythrocytes
AUTOR(ES)
Field, Michael
RESUMO
Preincubating turkey erythrocytes with cholera toxin alters their adenylate cyclase (EC 4.6.1.1) system: basal activity, maximal epinephrine-stimulatable activity, and affinity of the enzyme reaction for epinephrine are all increased. Pretreatment of erythrocytes with choleragenoid prevents these changes. Cholera toxin does not alter [3H]epinephrine uptake by intact erythrocytes. The increase in epinephrine-stimulatable cyclase activity appears to occur at the expense of fluoride-stimulatable activity, which is decreased by the toxin. In lysates from both toxin-treated and control cells, maximally stimulating amounts of epinephrine and fluoride, when added in combination, have a nearly additive effect on cyclase activity. These observations suggest that the adenylate cyclase system of the turkey erythrocyte may exist in two interconvertible forms, one that is catecholamine-responsive but fluoride-insensitive, and another that is fluoride-sensitive but not coupled to catecholamine receptors. Cholera toxin appears to stabilize the enzyme in its hormone receptor-coupled form.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=388673Documentos Relacionados
- Biochemical Characterization and Cytochemical Localization of a Catecholamine-Sensitive Adenylate Cyclase in Isolated Capillary Endothelium
- Reconstitution of catecholamine-sensitive adenylate cyclase activity: interactions of solubilized components with receptor-replete membranes.
- Studies on the Mode of Action of Cholera Toxin: EFFECTS ON SOLUBILIZED ADENYLATE CYCLASE
- Anti-alprenolol anti-idiotypic antibodies bind to beta-adrenergic receptors and modulate catecholamine-sensitive adenylate cyclase.
- Antibodies to the beta-adrenergic receptor: attenuation of catecholamine-sensitive adenylate cyclase and demonstration of postsynaptic receptor localization in brain.
