Enzymes: Special Proteins SWBAT Determine the functions of enzymes Determine enzyme regulation Determine the effect of temperature, pH, and enzyme/substrate concentration on enzyme activity

Properties of Enzymes Properties They are proteins Highly specific Have active site Reused/ remains unchanged LOWERS ACTIVATION ENERGY!!! Energy required to start a chemical reaction

How Enzymes Work Substrate – Attaches to the active site of an enzyme Active Site – the pocket or groove, that the substrate fits into Like a lock and key: enzyme/substrate combination allows reaction to occur like the correct key in a lock opens a door

Enzyme Action: Steps Enzyme attaches to its specific substrate and fits snugly within the active (binding) site. Enzyme and substrate interact Products are formed and released.

Enzymes in Depth Enzymes are the biological substance (proteins) that act as catalysts and help complex reactions occur everywhere in life

Enzymes are recycled and reused many times for the same type of reaction (never used up) Example: Sucrase converts sucrose  glucose + fructose Sucrase remains unchanged

Factors that affect enzymes Factors that affect the strength of an enzyme: pH Temperature Concentration of enzymes Concentration of Substrate

Temperature Temperature Each enzyme has an optimum temperature in which it works the best

Also a range of temperature in which it will work When the temperature drops/cools, activity of enzyme decreases/slows down When temperature increases Rate of reaction increases Then decreases Then stops (Denature) Most Biological Enzymes work in a temperature of 37°C

pH Most of biological enzymes work in a pH of 7, but there are some exceptions (Pepsin and Trypsin) Enzymes are affected by pH and have an optimum pH If the pH goes above or beyond the range, the enzyme becomes denatured

Concentration of Substrate and Enzymes The rate of reaction of the enzyme can be increased by increasing the concentration of the enzyme After a while the rate of reaction becomes constant At this point , the rate of the reaction can be increased only by increasing the concentration of the substrate

When Enzymes No Longer Work Environmental factors can change an enzyme. This process is called denaturation. Denatured enzymes no longer work. Example of Enzymes in action