title: Denaturation studies by fluorescence and quenching of thermophilic protein NAD+-glutamate dehydrogenase from Thermus thermophilus HB8.
abstract: Fluorescence techniques have been used to study the structural characteristics of many proteins. The thermophilic enzyme NAD-glutamate dehydrogenase from Thermus thermophilus HB8 is found to be a hexameric enzyme. Fluorescence spectra of native and denatured protein and effect of denaturants as urea and guanidine hydrochloride on enzyme activity of thermophilic glutamate dehydrogenase (t-GDH) have been analyzed. Native t-GDH presents the maximum emission at 338 nm. The denaturation process is accompanied by an exposure to the solvent of the tryptophan residues, as manifested by the red shift of the emission maximum. Fluorescence quenching by external quenchers, KI and acrylamide, has also been carried out.
authors.affiliation: División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Ruiz
authors.forename: Juan
authors.initials: J
authors.lastname: Ferrer
authors.forename: Carmen
authors.initials: C
authors.lastname: Pire
authors.forename: Francisco I
authors.initials: FI
authors.lastname: Llorca
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Bonete
mesh_terms: D020106:Acrylamide / Q000737:chemistry / Q000494:pharmacology; D005453:Fluorescence; D005456:Fluorescent Dyes; D005969:Glutamate Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D019791:Guanidine / Q000494:pharmacology; D009243:NAD / Q000737:chemistry / Q000378:metabolism*; D011193:Potassium Iodide / Q000737:chemistry / Q000494:pharmacology; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D020673:Protein Renaturation / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013696:Temperature; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D005456:Fluorescent Dyes; D009243:NAD; D011193:Potassium Iodide; D020106:Acrylamide; D005969:Glutamate Dehydrogenase; D019791:Guanidine