1. Enzymes
1.1. Structure
1.1.1. Enzymes are proteins with a specific three-dimensional shape. This shape allows them to catalyze reactions.
1.2. Active Site
1.2.1. Lock-and-Key Model: The enzyme’s active site is rigid and fits only specific substrates like a lock fits a key.
1.2.2. Induced Fit Model: The enzyme’s active site is flexible and changes shape to fit the substrate perfectly when it binds.
1.3. Specificity
1.3.1. Enzyme Specificity: Each enzyme binds to only one type of substrate, ensuring that only the correct reaction occurs.
2. Substrates
2.1. Binding to Active Site
2.1.1. Substrate Binding: The substrate binds to the enzyme's active site through weak chemical bonds hydrogen bonds, van der Waals forces, forming a temporary complex.
2.2. Role in Reactions
2.2.1. Enzyme Catalysis: The enzyme speeds up the reaction by lowering the activation energy required for the reaction to proceed.
2.2.2. Product Formation: The substrate is transformed into products, and these products are released from the enzyme after the reaction.
3. Enzyme-Substrate Complex Formation
3.1. Temporary Complex
3.1.1. Enzyme-Substrate Complex: When the substrate binds to the enzyme, a temporary complex is formed. This complex facilitates the chemical reaction.
3.2. Product Release
3.2.1. Reaction Complete: After the reaction occurs, the enzyme releases the products and is ready to bind to new substrates, remaining unchanged by the reaction.
4. Factors Affecting Enzyme Activity
4.1. Enzyme Concentration
4.1.1. More enzyme increases the reaction rate, but once all substrates are bound, adding more enzymes has no effect.
4.2. Substrate Concentration
4.2.1. substrate increases the rate until the enzymes are saturated, after which the rate plateaus.
4.3. Temperature
4.3.1. Higher temperatures speed up reactions until a certain point; beyond that, enzymes lose their shape and activity.
4.4. pH
4.4.1. Enzymes work best at specific pH levels. Deviating from this reduces their efficiency by altering their structure.