MODOS DE ACCIÓN ENZIMÁTICA. Llave -Cerradura y Ajuste Inducido.
Introduction to Enzymatic Action Models
Overview of Enzymatic Action
- The discussion focuses on enzymatic action, specifically the lock-and-key and induced fit models. The substrate binds to the enzyme, forming an enzyme-substrate complex that resolves into products while regenerating the enzyme for further reactions.
Lock-and-Key Model
- The lock-and-key model, proposed by Emil Fischer in 1893, describes a rigid active site on the enzyme that perfectly fits a specific substrate. This model remains relevant due to its simplicity and effectiveness in explaining enzymatic specificity.
- In this model, the substrate fits into the active site like a key in a lock, leading to catalysis and product release while allowing the enzyme to return to its original state for subsequent reactions.
- It emphasizes high specificity; each enzyme has an active site designed for one particular substrate. Minor mutations affecting amino acids at the active site can significantly alter enzymatic efficiency.
Limitations of Lock-and-Key Model
- Despite its utility, this model struggles with rapid enzymatic kinetics since it assumes rigid interactions between enzymes and substrates which may not always occur in dynamic environments.
Induced Fit Model
Introduction of Induced Fit Concept
- Proposed by Daniel Koshland in the late 1950s, the induced fit model modifies the lock-and-key concept by suggesting that both enzyme and substrate undergo conformational changes upon interaction. This flexibility allows for better fitting during catalysis.
Mechanism of Induced Fit
- In this model, when an enzyme encounters a substrate, they do not need perfect alignment initially; instead, they adjust their shapes upon contact to facilitate catalysis effectively. This results in faster reaction rates compared to rigid models like lock-and-key.
- The process involves initial contact followed by conformational adjustments that enhance catalytic activity and lead to product formation while allowing enzymes to be reused with other substrates afterward.
Advantages Over Lock-and-Key Model