par Barel, André 
;Turneer, Mireille;Dolmans, Marcel
Référence European journal of biochemistry / FEBS, 30, 1, page (26-32)
Publication Publié, 1972
;Turneer, Mireille;Dolmans, Marcel Référence European journal of biochemistry / FEBS, 30, 1, page (26-32)
Publication Publié, 1972
Article révisé par les pairs
| Résumé : | The extrinsic fluorescence of a bound dye, 2‐p‐toluidinylnaphthalene‐6‐sulfonate was used in order to study and to compare the hydrophobic sites on the surface of bovine α‐lactalbumin and egg‐white lysozyme. Both α‐lactalbumin and lysozyme bind one mol toluidinylnaphthalenesulfonate per mol protein, as determined fluorimetrically. The dissociation constants of the protein · dye complex for the two proteins are similar (0.3 to 0.5 mM), indicating a moderate binding of the dye to lysozyme and α‐lactalbumin. Considering the fluorescence of the protein · dye complex and the position of the maximum in the emission spectrum, it was found that the binding site on α‐lactalbumin was more hydrophobic than lysozyme. Binding experiments of lysozyme with toluidinylnaphthalenesulfonate in the presence of a competitive inhibitor (N‐acetyl‐d‐glucosamine) and measurements of bacteriolytic activity in the presence of this dye, suggest that the binding site on lysozyme did not significantly overlap with the area involved in the catalytic site. The intensity of fluorescence of the bound dye in α‐lactalbumin is diminished to a small extent by the presence of various sugars (glucose, lactose and galactose). The dissociation constant of the α‐lactalbumin · dye complex is identical in the presence or in the absence of these sugars. Copyright © 1972, Wiley Blackwell. All rights reserved |
