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Enzymes

Enzymes. Question:. What are enzymes ?. Enzymes. Answer: 1. Proteins: most enzymes are proteins , primarily tertiary and quaternary structures . 2. Catalyst: chemical agent that accelerates a reaction without being permanently changed in the process. Enzymes.

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Enzymes

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  1. Enzymes

  2. Question: • What are enzymes?

  3. Enzymes Answer: 1. Proteins: most enzymes are proteins, primarilytertiaryandquaternary structures. 2. Catalyst:chemical agent that accelerates a reaction without being permanently changed in the process.

  4. Enzymes 3. Selective: enzymes are specific for which they will catalyze(Specificity - depends upon 3D shape). 4. Recycled:enzymes are reusable. 5. “ase” endings: examples: sucrase maltase lactase

  5. Question: • How do enzymes work?

  6. Enzymes Answer: • Enzymes speed up the cell’s chemical reactions by lowering the free energy of activation.

  7. Without Enzyme With Enzyme Free Energy Free energy of activation Reactants Products Progress of the reaction Enzymes

  8. Enzyme Substrate Substrate • The substance (reactant) an enzyme acts on.

  9. Substrate Enzyme Active Site Active Site • A restricted regionof an enzyme molecule which binds to the substrate.

  10. Active Site substrate Enzyme induced fit Induced Fit • Achange in the configuration of an enzyme’sactive site(H and ionic bonds are involved). • Induced by the substrate.

  11. substrate (sucrose) + enzyme (sucrase)  enzyme-substrate complex  products + enzyme and + sucrase glucosefructose Enzymatic Reaction

  12. What Affects Enzyme Activity? • Three factors: 1. Environmental Conditions 2. Cofactors and Coenzymes 3. Enzyme Inhibitors

  13. 1. Environmental Conditions • Enzymatic reactions are very specific. The following environmental conditions affect enzymatic reactions: 1. Temperature (extremes most dangerous): - high temps may denature theenzyme. 2. pH (most like 6 - 8 pH - neutral) 3. Ionic concentration (salt ions)

  14. 2. Cofactors and Coenzymes • Inorganic substances (zinc, iron) and vitamins (respectively) are sometimes need for proper enzymatic activity. • Example: Iron must be present in the quaternary structure-hemoglobin in order for it to pick up oxygen.

  15. Substrate Enzyme Competitive inhibitor 3. Enzyme Inhibitors • Two examples: a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrateand compete with it for the active site.

  16. Noncompetitive Inhibitor Substrate Enzyme active site altered 3. Enzyme Inhibitors b. Noncompetitive inhibitors: Inhibitors that do not enter the active site, but bind to another partof the enzyme causing the enzyme to change its shape, which in turn alters the active site.

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