Introduction

Enzymes are a crucial part of biotechnology applications. Measuring the rate of enzyme-catalyzed reactions is key to understanding how enzymes work and their potential applications. Enzyme kinetics is the study of the rate at which enzymes catalyze reactions. Traditional models of enzyme kinetics have been used for many years, but recent advancements have offered more accurate models. In this blog post, we will compare traditional and advanced models of enzyme kinetics.

Traditional Models of Enzyme Kinetics

The traditional enzyme kinetic model is called Michaelis-Menten kinetics, named after two scientists who first proposed it in the early 1900s. This model assumes that the formation of the enzyme-substrate complex is the first step in the reaction and that the reaction follows the law of mass action.

The Michaelis-Menten model is based on three assumptions:

1. The enzyme and the substrate are in equilibrium with each other.
2. The amount of enzyme is constant.
3. The reaction reaches a steady-state.

This traditional model has a few limitations. It only works for simple reactions with a single substrate and doesn't account for the effect of enzyme inhibitors. It can also be challenging to determine the maximum rate of reaction and the Michaelis constant, which describes the enzyme's affinity for the substrate.

Advanced Models of Enzyme Kinetics

Recent advancements have led to more advanced models of enzyme kinetics that overcome the limitations of the traditional model. One such model is the Briggs-Haldane model. This model incorporates the possibility of the formation of a complex between the enzyme, the substrate, and an inhibitor.

The Briggs-Haldane model is based on four assumptions:

1. There is a fast equilibrium between the enzyme, the substrate, and the intermediate complex.
2. The intermediate complex is formed irreversibly.
3. The rate of product formation is proportional to the intermediate complex concentration.
4. The inhibitor does not affect the reaction between the intermediate complex and the product.

The Briggs-Haldane model is more accurate than the Michaelis-Menten model as it can account for multiple substrates and inhibitors. However, it still has limitations, such as the assumption of irreversible formation of the intermediate complex.

Conclusion

Advanced models of enzyme kinetics offer more accurate measurements of enzyme reactions, but they are more complicated and require more data to fit the model. Traditional models such as the Michaelis-Menten model are still used in many cases where simplicity is key. Overall, the choice of which model to use depends on the complexity of the reaction and the accuracy required.

References

1. Michaelis, L., & Menten, M. L. (1913). Die kinetik der invertinwirkung. Biochem. Z, 49, 333-369.
2. Briggs, G. E., & Haldane, J. B. (1925). A note on the kinetics of enzyme action. Proceedings of the Royal Society. Series B, Containing Papers of a Biological Character, 104(733), 1-4.
3. Cornish-Bowden, A. (2014). Fundamentals of enzyme kinetics. John Wiley & Sons.