title: Concentration regimes and denaturation effects on the conformational changes of α-chymotrypsin by viscosity and dynamic light scattering measurements.
abstract: This work focused on the conformational changes of α-chymotrypsin from bovine pancreas for various concentrations as well as the effects of chemical denaturation and organic solvents using both of viscosity and dynamic light scattering techniques. A wide range of concentrations varying between 0.1 and 30 mg/ml is tested to determine the critical concentration c** that separates the extremely dilute regime to the dilute regime and the overlapping concentration c* that separates the dilute regime to the semi-dilute regime. The knowledge of α-chymotrypsin folding process is followed for a range of chemical denaturant concentrations varying from 1 to 6 M. We showed that the α-chymotrypsin folds through a cooperative two-state transition without detectable kinetic intermediates and the formation of 50% unfolded happens for 5.5 M of urea or guanidinium chloride (GdmCl) concentrations. The action modes of the acetonitrile on the conformational changes of α-chymotrypsin are also achieved for concentrations varying between 10 and 50%.
authors: Laboratoire de Physique de la Matière Molle, Faculté des Sciences de Tunis, Campus Universitaire, 2092, Tunisia. naoufel-ghaouar@lycos.com
authors: N
authors: N
authors: Ghaouar
authors: S
authors: S
authors: Elmissaoui
authors: A
authors: A
authors: Aschi
authors: A
authors: A
authors: Gharbi
mesh_terms: D000097:Acetonitriles / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002918:Chymotrypsin / Q000032:analysis* / Q000737:chemistry*; D019791:Guanidine / Q000494:pharmacology; D057446:Hydrodynamics; D008027:Light; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D012542:Scattering, Radiation; D012997:Solvents; D013696:Temperature; D014508:Urea / Q000494:pharmacology; D014783:Viscosity / Q000187:drug effects
chemical_list: D000097:Acetonitriles; D012997:Solvents; D014508:Urea; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; D019791:Guanidine; C032159:acetonitrile