title: Impact of macromolecular crowding on structure and properties of pepsin and trypsin.
abstract: The change of conformation of pepsin and trypsin in absence and presence of a high molecular crowding agent has been characterized using dynamic light scattering (DLS). Structural properties were investigated as a function of chemical denaturant concentrations, the guanidine hydrochloride (GdmCl). The results showed that Ficoll 400, macromolecular crowding, has a strong effect on the chemical denaturation process of these two proteins. The changes of measured hydrodynamic radius are attributed to the enhancement effect of the crowder agent due to the excluded volume effects. The data proved that the large size of a macromolecular crowder plays a crucial role on the conformation of a protein in its unfolded states. The values of interactions Parameter kdof complex particles and a number of proteins nprattached on the Ficoll 400 measured in different GdmCl concentrations. The effect of aging on the structure of complex are studied by small angle light scattering (SALS).
authors.affiliation: Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES16 Laboratoire Physique de la Matière Molle et de la Modélisation Électromagnétique, 2092 Tunis, Tunisia.
authors.forename: Wala
authors.initials: W
authors.lastname: Gtari
authors.affiliation: Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES16 Laboratoire Physique de la Matière Molle et de la Modélisation Électromagnétique, 2092 Tunis, Tunisia.
authors.forename: Houda
authors.initials: H
authors.lastname: Bey
authors.affiliation: Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES16 Laboratoire Physique de la Matière Molle et de la Modélisation Électromagnétique, 2092 Tunis, Tunisia. Electronic address: Aschi13@yahoo.fr.
authors.forename: Adel
authors.initials: A
authors.lastname: Aschi
authors.affiliation: Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES16 Laboratoire de physiologie animale, UR Physiologie environnementale et biorythmes, 2092 Tunis, Tunisia.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Bitri
authors.affiliation: Université de Tunis El Manar, Faculté des Sciences de Tunis, LR99ES16 Laboratoire Physique de la Matière Molle et de la Modélisation Électromagnétique, 2092 Tunis, Tunisia.
authors.forename: Tahar
authors.initials: T
authors.lastname: Othman
mesh_terms: D000067493:Dynamic Light Scattering; D005362:Ficoll / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry; D057446:Hydrodynamics; D007700:Kinetics; D010434:Pepsin A / Q000737:chemistry* / Q000378:metabolism; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D055672:Static Electricity; D014357:Trypsin / Q000737:chemistry* / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D005362:Ficoll; D014357:Trypsin; D010434:Pepsin A; D019791:Guanidine
keywords: Aging effect; Chemical denaturation; Dynamic light scattering; Excluded volume effect; Macromolecular crowding; Small angles static light scattering