Enzymes: Biological Catalysts

• Enzymes are biological catalysts that speed up chemical reactions without being used up.
• They lower the activation energy needed for a reaction to proceed.

Activation Energy

• Activation energy is the "energy barrier" that must be overcome for a reaction to proceed.
• A catalyst or enzyme lowers the activation energy.
• Reactions occur more readily with a catalyst or enzyme.

Reactions and Enzymes

• Reactants are converted into products.
• Enzymes speed up the reaction.

Enzyme Characteristics

• Enzymes are usually globular proteins.
• They are highly specific to the reactions they catalyze.
• Each enzyme has a thermal and pH optimum for activity.
• Temperatures above the optimum can denature the enzyme by changing its tertiary structure.
• High temperature changes can cause irreversible denaturation.
• Lower temperatures reduce the reaction rate.
• Non-optimal pH values can also inactivate enzymes.
• Certain poisons can block enzyme function.

Examples of Enzyme Activity

• Pepsin is an enzyme that works best in acidic pH.
• Pancreatic lipase works best in a slightly alkaline pH.
• Frog and human enzymes have thermal optima around 30-40°C.

Historical Context and Importance

• Enzymes were first recognized in the 19th century.
• The term "enzyme" comes from the Greek word meaning "in yeast."
• Even simple bacteria have over 1,000 enzymes, with more complex organisms having even more.

Enzymes in Practical Applications

• Enzymes can be used outside of living organisms.
• Meat tenderizers contain papain, which pre-digests proteins.
• Fresh pineapple contains bromelain, which can affect the tongue and prevent gelatin from setting.
• Enzymes are also used in laundry detergents to break down protein-based stains.
• Historically, enzymes have been used in processes like wine and cheese production.

Induced-Fit Model

• The induced-fit model describes an enzyme-catalyzed reaction.
• Enzymes and substrates undergo dynamic modifications during the transition state in the active site.
• The enzyme itself is not destroyed or changed during the reaction.
• Enzyme names often correspond to the substrate and end in "-ase."

Cheese Making

• Cheese making involves separating the solid portion (curd) from the liquid (whey).
• The curd is primarily casein, a protein.
• Two types of cheese: sour-milk and rennet cheese.

Cheese Production Steps

• COAGULATION: Letting the milk sit
• CUTTING: Cut mixture up and let it sit
• HEATING: Heat to 100-102 degrees
• DRAINING: Separate the curd from the whey
• STIRRING: Keep stirring until mixture gets hard
• SALTING: Use salt as natural preservation
• PRESSING: Removing any excess fluid
• AGING: Letting the cheese age and develop unique flavor

Bile and Fat Digestion Experiment

• The experiment investigates milk fat digestion by pancreatic lipase and the role of bile.
• Lipase, secreted by the pancreas, catalyzes the hydrolysis of triglycerides into fatty acids and glycerol.
• Bile, secreted by the liver, emulsifies fats, breaking large droplets into smaller ones.
• Emulsification increases the surface area for lipase to act on.

Procedure of Bile and Fat Digestion Experiment

• Use litmus "PH" is blue in Alkaline/Red in Acidic.
• Several tubes, each in different environments
• Mix it all + add lipase last
• Leave for 1 hour then record

Key Concepts in the Experiment

• Lipase breaks down fat into fatty acids.
• Bile aids in emulsification, but isn't an acid.
• Fatty acids are components of broken down fat

Additional notes on the experiment

• Once the bile was added it caused pH to change.
• Lipase helps function in the Pancreas where the pH is 7
• It digested greater when litmus cream PH was adjusted to 8
• Digestion is breaking down simpler while Emulsification is using digestion
• Lipolysis is breaking down fat into component parts

Cheese Making and Enzyme Characteristics

• Enzymes are usually globular proteins.
• Not all enzymes are catalysts, and vise versa.
• Active sight is the region on enzyme that fits substrate.
• The process of breaking a polymer down into monomers using water is called hydrolisis
• The process of breaking fat down into smaller components is lipolysis