Enzyme Structure & Function PDF

# Enzyme Structure & Function ## Enzymes - Biomolecules that speed up chemical reactions in cells. - Function through catalysis. - Many end with the suffix "-ase". ## Active Site - The area on an enzyme that recognizes and binds to the substrate molecule. ## Substrate - A molecule that an enzy...

# Enzyme Structure & Function ## Enzymes - Biomolecules that speed up chemical reactions in cells. - Function through catalysis. - Many end with the suffix "-ase". ## Active Site - The area on an enzyme that recognizes and binds to the substrate molecule. ## Substrate - A molecule that an enzyme catalyzes reactions for. - Each enzyme is specific to a particular substrate. ## Enzyme-Substrate Complex - Formed when an enzyme binds to its substrate. ## Lock-and-Key Model - The active site and substrate have a perfect fit, like a lock and key. ## Induced-Fit Model - The active site changes shape slightly to accommodate the substrate, strengthening the bond. ## Catalytic Site - Amino acid residues within the active site that directly catalyze the reaction. ## Binding Site - Amino acid residues that bind and orient the substrate. ## Examples of Enzymes - Amylase - Digests starch in saliva - Trypsin - Breaks down proteins in the small intestine - Helicase - Unwinds DNA during replication - Lactase - Breaks down lactose (sugar) ## Functions of Enzymes in the Body - **Digestion** - Amylase, trypsin, pepsin, lactase, etc. - **Cell Division** - Cyclin-dependent kinases (Cdks) - **Nervous Function** - Acetylcholinesterase - **DNA Replication** - Helicase, DNA polymerase, etc. ## Catalysis and Activation Energy - Enzymes lower the activation energy required for a reaction to occur. - This is achieved by modifying the reactants into a transition state. ## Protein Structure ### Primary Structure: - The sequence of amino acids in a polypeptide chain. ### Secondary Structure: - The folding pattern of the polypeptide chain (e.g., alpha helix, beta pleated sheet). ### Tertiary Structure: - The overall three-dimensional shape of a single polypeptide chain. ### Quaternary Structure: - The arrangement of multiple polypeptide subunits in a protein. ## Additional Information - Not all enzymes end with the suffix "-ase". Notable exceptions include pepsin, pepsinogen, trypsin, and rennin. - The difference between the catalytic site and the binding site is that the catalytic site is responsible for directly catalyzing the reaction, while the binding site is responsible for binding and orienting the substrate.