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Enzymes

Enzymes are proteins that catalyze the rate of chemical reactions by decreasing the amount of activation energy required. They are specific, reusable, and not permanently changed in the process. This article explores the role of enzymes, how they work, enzyme-substrate complex, and factors affecting enzyme activity.

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Enzymes

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  1. Enzymes

  2. What are enzymes? Enzymes are proteins (tertiary and quaternary structures) that catalyze (act as catalysts)the rate of a chemical reaction (increase). They do this by decreasingthe amount of activation energy required for a reaction. Not permanentlychanged in the process

  3. Enzymes • Are specific for what they will catalyze • AreReusable • End in –ase -Sucrase -Lactase -Maltase

  4. Enzymes are very specific... • For example, the lipase substrate (lipids) would not attach to amylase.

  5. How do they work? Activation energy is energy that chemicals need in order to begin a reaction Example: Frogs leaping over a pile of rocks. The higher the barrier (activation energy) the less frogs can get over (or less product is created).

  6. How do enzymes Work? Enzymes work by weakening bonds which lowers activation energy

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

  8. H2O2 is a breakdown product of aerobic respiration. Catalase breaks down H2O2.Catalase is in peroxisomes (in cells) and rid the body of toxins.Peroxisomes are concentrated in the liver and the kidneys.https://www.youtube.com/watch?v=ok9esggzN18

  9. Enzyme-Substrate Complex Enzyme An enzyme acts on the substrate (chemical substance) Joins Substrate

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

  11. Enzyme-Substrate Complex: Lock and Key Theory -The substrate attaches to the enzyme’s active site. -Enzymes and substrates fit like a lock and key.

  12. Without enzymes, every day reactions would be far too slow for us to survive. • Unable to break down toxic wastes in a timely manner. • Unable to metabolize our food fast enough. Life cannot exist without enzymes!

  13. Induced Fit Theory the enzyme changes its shape slightly to create a more secure bond with substrate, and then the chemical reaction follows.

  14. Induced Fit • A change in the shape of an enzyme’s active site • Induced by the substrate

  15. After the chemical reaction, the product is released from the enzyme. The enzyme is free to carry on the same chemical reaction again and again (enzymes can be reused).

  16. What Affects Enzyme Activity? • Four factors: 1. Environmental Conditions 2. Cofactors 3. Coenzymes 4. Enzyme Inhibitors

  17. 1. Environmental Conditions A. Extreme Temperatures are the most dangerous - high tempsmay denature (unfold) the enzyme. B. pH (most like 6 - 8 pH near neutral) C. Ionic concentration (salt ions)

  18. Factors that Affect Enzymes -Two factors that affect enzyme productivity are pH and temperature. -Enzymes thrive best within certain temperature and pH ranges, and cease functioning in others. Example: people die of fevers not because of the high temperatures, but because the enzymes in their body do not function properly once the temperature gets too high.

  19. Examples of Enzymes

  20. 2. Cofactors and 3.Coenzymes • Inorganic substances (zinc,magnesium,copper,iron)and organicvitamins (respectively) are sometimes need for proper enzymatic activity. • Example 1: Iron must be present in the quaternary structure-hemoglobin in order for it topick up oxygen. zinc must be present to break down alcohol (alcohol dehydrogenase) Example 2: The coenzymes make up a part of the active site, since without the coenzyme, the enzyme will not function. • vitamin B-12 - vitamin • coenzyme B-12 - coenzyme • Methyl group transfer - function

  21. Enzyme Competitive inhibitor Two examples of Enzyme Inhibitors Many drugs are enzyme inhibitors as well as chemicals such as herbicides and pesticides and neurotoxins. a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrateand compete with it for the active site. Substrate

  22. b. Noncompetitive inhibitors: Inhibitors that do not enter theactive site, but bind toanother partof the enzymecausing the enzyme to change its shape, which in turn alters the active site. The most common uses for enzyme inhibitors are as drugs to treat disease, an example is drugs used in chemotherapy, viagra, and anti-epilepsy medication. Noncompetitive Inhibitor Enzyme active site altered Inhibitors Substrate

  23. Enzymes play a critical role in everyday life. Many heritable genetic disorders (diabetes, Tay-Sachs disease) occur because there is a deficiency or total absence of one or more enzymes. Other disease conditions (cancer) result because there is an excessive activity of one or more enzymes. Routine medical tests monitor the activity of enzymes in the blood, and many of the prescription drugs (penicillin) exert their effects through interactions with enzymes. https://www.youtube.com/watch?v=XUn64HY5bug

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