Related Experiment Video
Updated: Jun 6, 2025
09:19
RNA Catalyst as a Reporter for Screening Drugs against RNA Editing in Trypanosomes
Published on: July 22, 2014
8.4K
Understanding Ion-specific "Hofmeister" Effects in Enzyme Catalysis through using RNase A as a Paradigm Model
Bahareh Taghavi Shahraki1, Mazdak Khajehpour1
1Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
Summary
Salts influence biomolecules through ion-specific Hofmeister effects. This study reveals that while salts affect Ribonuclease A
Area of Science:
- Biophysical Chemistry
- Enzymology
- Protein Science
Background:
- Hofmeister effects describe how salts influence biomolecules in an ion-specific manner.
- Ion specificity impacts protein folding, precipitation, and phase separation.
- Molecular mechanisms of ion-specific effects on enzyme catalysis remain unclear.
Purpose of the Study:
- To investigate ion-specific effects on the enzymatic activity and folding free energy of Ribonuclease A (RNase A).
- To elucidate the relationship between ion-induced changes in protein folding and enzyme catalysis.
Main Methods:
- Developed a framework to quantify ion-specific effects on RNase A's catalysis of cCMP hydrolysis.
- Analyzed folding thermodynamics and Michaelis-Menten kinetic parameters.
Main Results:
- Both folding thermodynamics and kinetic parameters of RNase A exhibit ion-specific salt dependence.
- Ion-specific effects on protein folding and enzyme catalysis are not directly correlated.
- Protein folding changes reflect ion interactions with the overall protein surface.
- Enzyme activity changes indicate ion interactions with the active site or substrate.
Conclusions:
- Ion-specific effects modulate both RNase A folding and catalytic activity.
- The molecular basis for ion-specific effects on enzyme activity differs from those on protein folding.
- Understanding these distinct interactions is crucial for enzyme engineering and bioprocess design.
Related Concept Videos
01:13Introduction to Mechanisms of Enzyme Catalysis
8.0K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
8.0K
02:34Enzymes
80.8K
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
80.8K
01:13Induced-fit Model
80.4K
Most chemical reactions in cells require enzymes—biological catalysts that speed up the reaction without being consumed or permanently changed. They reduce the activation energy needed to convert the reactants into products. Enzymes are proteins, that usually work by binding to a substrate—a reactant molecule that they act upon.
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical...
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical...
80.4K
01:07Catalytically Perfect Enzymes
3.9K
The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at high-speed. Their catalytic efficiency values range from 108-109 M-1s-1. These enzymes are also called 'diffusion-controlled' as the only rate-limiting step in the catalysis is that of the substrate diffusion into the active site. Examples include triose phosphate isomerase, fumarase, and superoxide dismutase.
Most enzymes...
Most enzymes...
3.9K
02:47Ribozymes
11.2K
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can...
Ribozymes can...
11.2K
01:19Enzyme Kinetics
96.0K
Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...
96.0K