The unfolding and refolding of glutamate dehydrogenases from bovine liver, baker's yeast and Clostridium symbosium.
The unfolding behaviour of the hexameric glutamate dehydrogenases from bovine liver, Clostridium symbosium and baker's yeast in solutions of guanidinium chloride (GdnHCl) was studied. Changes in Mr studied by light-scattering indicate that, in each case, the hexamer dissociates to form trimers, which then dissociate to monomers at higher concentrations of GdnHCl. Dissociation to trimers is accompanied by a reversible loss of enzyme activity, but no gross structural changes can be detected by fluorescence or c.d. Dissociation to monomers is accompanied by large structural changes, and the loss of activity cannot be reversed by dilution. The parallel behaviour of all three enzymes shows that the previously noted inability of the isolated subunits of the bovine liver enzyme to refold [Bell & Bell (1984) Biochem. J. 217, 327-330] is not a result of any modification of the enzyme as a result of import into mitochondria, since the C. symbosium and baker's-yeast enzymes do not undergo any such post-translational translocation.
West
S M
SM
Department of Biological Science, University of Stirling, Scotland, U.K.
Price
N C
NC
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D003013:Clostridium / Q000201:enzymology*; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013050:Spectrometry, Fluorescence
D006146:Guanidines; D005969:Glutamate Dehydrogenase; D019791:Guanidine