Porphyrin biosynthesis-immobilized enzymes and ligands-X. A novel approach to the study of the relationship between the quaternary structure of aminolaevulinate dehydratase and its...

• Autores: Del C. Batlle, A.M.; Stella, A.M.; Ferramola, A.M.; Sopena, Y.; De Xifra, E.A.W.; Sancovich, H.A.
• Año de publicación: 1978
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Int. J. Biochem. 1978;9(6):401-406
• Materia: enzyme; porphobilinogen synthase; porphyrin; animal experiment; cattle; liver; Animals; Cattle; Chemistry; Enzymes, Immobilized; Hydrogen-Ion Concentration; Kinetics; Liver; Macromolecular Substances; Models, Chemical; Porphobilinogen Synthase; Protein Denaturation; Sepharose; Solubility
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

1. 1. Evidence for dissociation, renaturation, re-association and re-hybridization of bovine liver aminolaevulinate dehydratase attached to Sepharose 4B is reported. 2. 2. When insolubilized enzyme was treated with 3 and 6 M urea, non covalently bound subunits were dissociated and detected in the eluate; these subunits can be re-associated into a soluble functioning enzyme with a specific activity close to that of the original pure soluble dehydratase preparation. 3. 3. After being washed with a renaturing buffer mixture, the matrix-bound subunits recovered a level of enzymatic activity equal to 50 and 20% of that of the immobilized native aminolaevulinate dehydratase. 4. 4. The reversibility of the dissociation process was investigated. Bound-subunits dehydratase can associate with nascent soluble bovine liver aminolaevulinate dehydratase subunits in situ. The product of such treatment, bound-re-associated enzyme, has the same activity as that of the original bound-dehydratase. The matrix-bound-dissociated bovine liver enzyme was also re-hybridized with soluble dehydratase subunits from E. gracilis. 5. 5. The apparent Km and optimum pH of the immobilized subunits were the same as those of the bound-octameric enzyme. 6. 6. A scheme is proposed, explaining the sequence of reactions leading from the bound-octameric dehydratase to the possible different derivatives, formed during the dissociation and re-association experiments. © 1978.
Fil:Del C. Batlle, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Stella, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Ferramola, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Sancovich, H.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.