Enzymes Part 1 Chapter 3

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ENZYMES!!! A special type of protein…??? In order for a protein to work at its SPECIFIC JOB, it must have….??? Because an enzyme is a protein, it MUST have….??? Can any key unlock the door to your house??? Can any substrate/reactant fit into a specific enzyme? How many different enzymes do we have???

Proteins: Enzymes What is a chemical reaction? Do they happen on their own? If we stare at the piece of paper, are we going to be able to make the oxygen molecules in the air collide with the cellulose in the paper? What do we need to do? What are reactants? What are products?

Proteins Biological catalysts that speed up the rate of chemical reactions They help make products faster! Never used up! “Matchmaker” ENZYMES!!!

Enzymes Biological catalyst What is a catalyst? Every metabolic rxn in organisms use enzymes GLOBULAR PROTEINS review levels of protein structure Review characteristics of globular proteins Always end in “-ASE” Examples: ATP synthase Lactase Sucrase Amylase Carbonic anhydrase DNA polymerase DNA helicase RNA polyermase DNA ligase What is a catalyst? Molecule that speeds up a chemical reaction Remains unchanged at end of RXN

Anatomy of an Enzyme Globular Active site Enzyme-substrate complex Hydrophilic R groups on the outside, hydrophobic R groups facing the interior of the enzyme Active site Region on enzyme where a specific molecule can bind (substrate) Allows for perfect fit SPECIFICITY Active site of an enzyme it SPECIFIC for a particular substrate (molecule) Enzyme-substrate complex When substrate fits into the SPECIFIC active site of an enzyme and chemical reaction begins to occur Combined structure of enzyme and substrate

Lock and Key Model vs. Induced Fit Hypothesis Modified Lock and Key Model 1959 Same as lock and key EXCEPT… ADDS the idea that enzyme and/or substrate can change shape slightly when substrate enters active site Ensures PERFECT fit Catalysis more efficient Lock and Key Model Original model for how an enzyme works Substrate fits into active like a key in a lock Enzyme (active site of enzyme) is specific for a particular substrate like a key is specific for a lock