Enzymes What are Enzymes Enzymes are proteins Used

Enzymes

What are Enzymes? • Enzymes are proteins • Used by the cell to speed up reactions. • Are biological catalysts • Remain unchanged by the reaction • Are reusable

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

Enzymes are proteins with a 3 dimensional shape. Their specific shape determines the substrate that it works with. Substrates are the substances that the enzymes act upon. Lipase acts on lipids. Maltase acts on maltose. Protease acts on proteins. Substrates Enzymes

Step by Step l l l The substrate binds to the enzyme at the active site Only certain substrates can fit the active site Enzyme-substrate complex forms Substrate reacts to form product Product is released

Substrate binds to the enzyme at the Active Site Enzyme substrate complex forms (substrate begins reaction) Product is released Enzyme can be used again

Enzymes The rate of enzyme activity depends not only on its 3 dimensional shape, but it also depends on other factors. temperature p. H concentration inhibitors

Temperature • Little activity at low temperature • Rate increases with temperature • Most active at optimum temperatures (usually 37°C in humans) • Enzymes denature (change shape) at high temperatures

Temperature 1. What is the optimal temperature for enzyme A? ____ 38 o. C 62 o. C 2. What is the optimal temperature for enzyme B? ____ 3. Knowing that room temperature is approximately 22 degrees Celsius, which enzyme would work best in your body? _____ A

p. H • Maximum activity at optimum p. H • Narrow range of activity • Most lose activity in low or high p. H

p. H Intestinal Protease Gastric Protease 1. What is the optimal p. H for the enzyme found in your stomach ? 3 2. What is the optimal p. H for the enzyme found in your intestine? 7. 8 3. What organic substance are both of these enzymes digesting? Proteins

Concentration • Increasing substrate concentration increases the rate of reaction • Maximum activity reached when all of enzyme combines with substrate

Inhibitors Competitive: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site Substrate Competitive inhibitor Enzyme

Inhibitors Enzyme Noncompetitive: Inhibitors that do not enter the active site, site but bind to another part of the enzyme causing the enzyme to change its shape, shape which in turn alters the active site Substrate active site altered Enzyme Noncompetitive Inhibitor

Inhibitors Competitive Inhibition Noncompetitive Inhibition

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