Enzymes Review Day

Terms from last POGIL “gonic” Reactions Biology, Sixth Edition Chapter 6, Energy and Metabolism “gonic” Reactions Reactions that require energy input are called endergonic if they need heat, they are endothermic If a reaction releases energy it is exergonic if the energy is released as heat, it’s exothermic. Terms from last POGIL

ATP Adenosine triphosphate It is a nucleotide 3 parts Nitrogen base (adenine) Ribose (5C sugar) 3 phosphate groups Energy of ATP is in these bonds Hydrolysis (adding water) breaks this bond making ADP + Pi This is called phosphorylation Biology, Sixth Edition Chapter 6, Energy and Metabolism

Energy Released by the Hydrolysis of ATP is Coupled to Other Reactions Biology, Sixth Edition Chapter 6, Energy and Metabolism

NAD+ / NADH & Oxidation / Reduction Reactions OilRig NAD+ / NADH & Oxidation / Reduction Reactions Reduction is the addition of electrons. Results in increased energy content Very common in metabolism e.g., NAD+ NADH e.g., FAD FADH2 Oxidation is the loss of electrons. e.g., NADH NAD+ e.g., FADH2 FAD Oxidation and reduction are often coupled as redox reactions. Biology, Sixth Edition Chapter 6, Energy and Metabolism

Enzymes Lower EA Activation energy (Ea) is the energy required to break the bonds to begin the reaction Biology, Sixth Edition Chapter 6, Energy and Metabolism

Result? Induced fit

Catalase AP Lab #2 Example of an enzyme (all enzymes end in ASE) Is found in all living things Used to break down toxins in the body For example, Catalase breaks down hydrogen peroxide in the body (it is a byproduct of metabolism) AP Lab #2

3.4 Notes! Having too little of an enzyme or having too much of an enzyme can have major consequences Sucrase (lack of it causes diarrhea, cramps & possibly slower growth in kids) Too much of an enzyme is wasteful for the cell So in order to maintain homeostasis, we need to regulate enzymes!

Inhibitors Chemicals Some naturally occur in cells (can regulate metabolism) Others are made in laboratories (used to treat diseases) Inhibitors bind to enzymes, which has an effect on the function of an enzyme.

Competitive Inhibition Inhibitor binds to the active site of an enzyme Induced fit occurs and enzyme is unable to bind to substrate. Reversible When inhibitor is in low amounts, it will leave the active site and then the substrate can bind.

Allosteric inhibition Inhibitor binds to an alternate site on the enzyme (not the active site), called the allosteric site. Still changes shape of enzyme, so substrate cannot bind to active site Also called noncompetitive inhibition

What can affect an enzyme? pH Temperature All enzymes have optimal conditions for optimal performance Remember enzymes are proteins, so if the tertiary level is changed, the enzyme loses its function