Alkaline unfolding and salt‐induced folding of bovine liver catalase at high pH
Reads0
Chats0
TLDR
The refolding/reconstitution studies showed that the salt-induced partially folded tetrameric intermediate shows significantly higher efficiency of refolding or reconstitution as compared to alkaline-denatured catalase in the absence of salts.Abstract:
We have studied the alkaline unfolding of bovine liver catalase and its dependence on ionic strength by enzymic activity measurements and a combination of optical methods like circular dichroism, fluorescence and absorption spectroscopies. Under conditions of high pH (11.5) and low ionic strength, the native tetrameric enzyme dissociates into monomers with complete loss of enzymic activity and a significant loss of α-helical content. Increase in ionic strength by addition of salts like potassium chloride and sodium sulphate resulted in folding of alkaline-unfolded enzyme by association of monomers to tetramer but with significantly different structural properties compared to native enzyme. The salt-induced tetrameric intermediate is characterized by a significant exposure of the buried hydrophobic clusters and significantly reduced α-helical content compared to the native enzyme. The refolding/reconstitution studies showed that the salt-induced partially folded tetrameric intermediate shows significantly higher efficiency of refolding/reconstitution as compared to alkaline-denatured catalase in the absence of salts. These studies suggest that folding of multimeric enzymes proceeds probably through the hydrophobic collapse of partially folded multimeric intermediate with exposed hydrophobic clusters.read more
Citations
More filters
Journal ArticleDOI
Attractive Protein-Polymer Interactions Markedly Alter the Effect of Macromolecular Crowding on Protein Association Equilibria
TL;DR: The results presented here provide the first experimental evidence for the existence of competition between a repulsive excluded volume interaction between protein and polymer, which tends to enhance association of dilute protein, and an attractive interaction betweenprotein and polymer that tends to inhibit protein association.
Journal ArticleDOI
8-anilino-1-naphthalene sulfonic acid (ANS) induces folding of acid unfolded cytochrome c to molten globule state as a result of electrostatic interactions.
TL;DR: This is the first experimental demonstration of ANS induced folding of unfolded protein and puts to question the usefulness of ANs for characterization/determination of partially folded intermediates of proteins observed under low pH conditions.
Journal ArticleDOI
Guanidinium chloride- and urea-induced unfolding of the dimeric enzyme glucose oxidase.
TL;DR: The GdmCl-stabilized compact dimeric intermediate of GOD showed an enhanced stability against thermal and urea denaturation as compared to the native GOD dimer, which is the first report where violation of the 2-fold rule has been observed for a multimeric protein.
Journal ArticleDOI
Comparison of guanidine hydrochloride (GdnHCl) and urea denaturation on inactivation and unfolding of human placental cystatin (HPC).
TL;DR: The activity and conformational change of human placental cystatin (HPC), a low molecular weight thiol proteinase inhibitor, has been investigated in presence of guanidine hydrochloride (GdnHCl) and urea and the urea induced denaturation followed two-state rule.
Journal ArticleDOI
Stabilization of quaternary structure and activity of bovine liver catalase through encapsulation in liposomes
TL;DR: In this paper, catalase was encapsulated in an aqueous phase of the phospholipid vesicle (liposome) to improve the stability of its tetrameric structure and activity.
References
More filters
Journal Article
Protein Measurement with the Folin Phenol Reagent
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
Book ChapterDOI
Molten globule and protein folding.
TL;DR: It is predicted and confirmed experimentally that the molten globule state can exist in a living cell and plays an important role in a number of physiological processes.
Journal ArticleDOI
Intermediates in the Folding Reactions of Small Proteins
Peter S. Kim,Robert L. Baldwin +1 more
TL;DR: Collapsed Forms (Molten Globules) and Local Unfolding Reactions.
Journal ArticleDOI
The denatured state (the other half of the folding equation) and its role in protein stability.
TL;DR: The denatured state plays a central role in all aspects of protein stability, including mutant effects, and a quantitative understanding of how amino acid sequence encodes protein structure will probably depend on a more complete picture of this complex, difficult‐to‐study state.
Journal ArticleDOI
Conformational states in .beta.-lactamase: molten-globule states at acidic and alkaline pH with high salt
Yuji Goto,Anthony L. Fink +1 more
TL;DR: Evidence is presented that beta-lactamase is close to fully unfolded at low ionic strength at the extremes of pH and that the presence of salt causes a cooperative transition to a conformation with the properties of a molten globule, namely, a compact state with native-like secondary structure but disordered side chains (tertiary structure).