Enzyme Function and Activation Energy

Proteins that speed up chemical reactions by lowering activation energy, they are not consumed in the reaction.

The initial energy input required to break down large molecules.

Enzymes bring substrates together and position them correctly for a reaction to occur.

Enzymes destabilize the substrate by reducing or oxidizing it, making it more likely to react.

The active site of an enzyme can change shape to fit a specific substrate.

High temperature, low pH, high pH, and salts can break bonds and denature enzymes.

The process of breaking bonds that hold an enzyme in its 3D shape, causing it to lose its functionality.

Cold temperatures reduce kinetic energy, leading to fewer collisions between enzyme and substrate, thus slow reaction rates.

Heat breaks hydrogen bonds, ionic bonds, and hydrophobic interactions, altering the shape of the active site.

Extreme pH levels (acidic or basic) disrupt ionic and hydrogen bonds, causing changes in the enzyme's 3D structure.

Extreme pH levels can disrupt an enzyme's structure by interfering with the hydrogen bonds, ionic bonds, and hydrophobic interactions that maintain its three-dimensional shape, leading to denaturation and loss of function.

Pepsin, a digestive enzyme in the stomach, works optimally at a low pH (acidic) environment. Amylase, a digestive enzyme found in the saliva and pancreas, operates best at a near-neutral pH.

Increasing substrate concentration initially increases enzyme activity as more substrate molecules are available to bind to the active sites of the enzyme and form enzyme-substrate complexes. However, as the substrate concentration increases, the enzyme becomes saturated with substrate molecules, and the rate of reaction plateaus.

Adding more enzymes can increase the rate of reaction until the point where there is no more substrate available to bind to. At this point, the reaction rate will plateau.

Inhibitors are molecules that decrease enzyme activity by binding to the enzyme and preventing it from functioning properly. Competitive inhibitors bind to the active site and block the substrate from binding. Non-competitive inhibitors bind to a different site on the enzyme, changing its shape and making it less effective.

Cofactors are inorganic ions (e.g., Ca2+, Zn2+, Mg2+) that are required for some enzymes to function. Coenzymes are organic molecules (e.g., vitamins) that assist enzymes by donating or accepting electrons or functional groups during a reaction.

Allosteric regulation refers to the control of enzyme activity through the binding of regulatory molecules to sites on the enzyme that are distinct from the active site. Activators bind to allosteric sites and increase enzyme activity, while inhibitors decrease activity.

Feedback inhibition is a type of metabolic control where the product of a metabolic pathway inhibits the activity of an enzyme earlier in the pathway. This prevents the overproduction of the product.

Increasing temperature generally increases enzyme activity to a point. The optimal temperature for an enzyme is the temperature at which it functions most effectively. Beyond the optimal temperature, enzyme activity decreases dramatically due to denaturation, which is the irreversible loss of enzyme structure and function.

Increasing pH generally increases enzyme activity to a point. The optimal pH for an enzyme is the pH at which it functions most effectively. Beyond the optimal pH, enzyme activity decreases dramatically due to denaturation, which is the irreversible loss of enzyme structure and function.