Bio13312 Biochemistry - Lecture Nine - Enzymes And Coenzymes

The "pocket" on the enzyme where the substrate fits is called the active site. This is where the enzyme and substrate interact and undergo a chemical reaction. The active site has a specific shape and chemical properties that allow it to bind with the substrate and facilitate the conversion of the substrate into a product. The active site plays a crucial role in enzyme activity and specificity, as it determines which substrates can bind and be catalyzed by the enzyme.

An apoenzyme refers to a protein that is inactive or nonfunctional without the presence of a co-factor or co-enzyme. In other words, it is the protein component of an enzyme that lacks the necessary non-protein component to carry out its catalytic function. The co-factor or co-enzyme is required to activate the apoenzyme and enable it to perform its specific biochemical reaction.

Catalysts are substances that lower the activation energy required for a chemical reaction to occur. By reducing the amount of energy needed for the reaction to start, catalysts increase the rate at which the reaction takes place. They do not change the overall energy change or favorability of the reaction, but rather facilitate the conversion of reactants into products by providing an alternative reaction pathway with lower energy barriers. Therefore, the correct answer is "Reduce activation energy."

Tight binding to either an enzyme or product is bad for catalysts because it can hinder the catalytic activity. In order for a catalyst to function effectively, it needs to be able to bind to substrates (reactants) and release products efficiently. If the binding is too tight, it can slow down the reaction or even prevent it from occurring altogether. Therefore, tight binding to either an enzyme or product is detrimental to the catalytic process.

In a favorable reaction, the products have lower energy than the reactants. This is because a favorable reaction is exothermic, meaning it releases energy. The reactants start with a higher energy level, and as the reaction progresses, energy is released and the products end up with a lower energy level. This decrease in energy is what drives the reaction forward and makes it favorable.

A combination of a protein and a co-factor/co-enzyme is called a holoenzyme. The co-factor or co-enzyme is a non-protein molecule that is necessary for the proper functioning of the protein. When the co-factor or co-enzyme is bound to the protein, it forms a functional unit known as a holoenzyme. The co-factor or co-enzyme often acts as a catalyst, assisting the protein in performing its specific biological function. Holoenzymes are essential in many biochemical reactions and are involved in various metabolic processes in living organisms.

Amino acids are organic compounds that contain both an amino group (-NH2) and a carboxyl group (-COOH). They are linked together by peptide bonds to form polypeptide chains, which fold into specific three-dimensional structures to create functional proteins. There are 20 different amino acids commonly found in proteins, each with unique properties that contribute to the overall structure and function of the protein.

Serine proteases are enzymes that break down proteins through hydrolysis. They use a combination of acid-base and covalent catalysis to facilitate this process. Acid-base catalysis involves the donation or acceptance of protons, which helps in the activation of water molecules for the hydrolysis reaction. Covalent catalysis involves the formation of a transient covalent bond between the enzyme and the substrate, stabilizing the transition state and facilitating the cleavage of the peptide bond. Therefore, the correct answer is acid-base and covalent catalysis.

The ionic interactions between the enzyme bound metal and the substrate can orient a substrate for reaction. This means that the metal ion can help position the substrate in a specific way that allows for a more efficient and effective reaction to occur. By orienting the substrate, the metal ion can increase the chances of the desired reaction taking place. This is a crucial step in enzyme catalysis as it helps to ensure that the reaction proceeds in the desired direction.