title: Ornithine carbamoyltransferase unfolding states in the presence of urea and guanidine hydrochloride.
abstract: Ornithine carbamoyltransferase folding/unfolding is a complex and not completely understood process. Our experimental results suggest that ornithine carbamoyltransferase interacts in a completely different way with urea and guanidine hydrochloride. In fact, we noticed that, increasing concentration from 0.0 to 8.0 M of the two additives, the enzyme follows a simple one-step transition mechanism in the presence of guanidine hydrochloride, with two macroscopic states (the native and the denatured one) significantly populated, whereas in the presence of urea a lot of different protein states can be detected and analyzed. Circular dichroism and UV-visible spectroscopy reveal a similar mechanism of perturbation at high temperature, with opening of hydrophobic core and a significant loss in α-helix structure in the presence of guanidine hydrochloride that cannot be found in the presence of urea.
authors.forename: D
authors.initials: D
authors.lastname: Barreca
authors.forename: G
authors.initials: G
authors.lastname: Laganà
authors.forename: S
authors.initials: S
authors.lastname: Ficarra
authors.forename: E
authors.initials: E
authors.lastname: Tellone
authors.forename: U
authors.initials: U
authors.lastname: Leuzzi
authors.forename: A
authors.initials: A
authors.lastname: Galtieri
authors.forename: E
authors.initials: E
authors.lastname: Bellocco
mesh_terms: D000818:Animals; D002942:Circular Dichroism; D004587:Electrophoresis, Agar Gel; D004789:Enzyme Activation / Q000187:drug effects; D005453:Fluorescence; D019791:Guanidine / Q000494:pharmacology*; D007700:Kinetics; D009954:Ornithine Carbamoyltransferase / Q000378:metabolism*; D017510:Protein Folding / Q000187:drug effects*; D017433:Protein Structure, Secondary; D012754:Sharks; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D014508:Urea / Q000494:pharmacology*
chemical_list: D014508:Urea; D009954:Ornithine Carbamoyltransferase; D019791:Guanidine