Enzymes

Enzymes Learning Target:

1. Recognize enzymes as catalysts:a. Protein molecules that function to lower

activation energy (increase rate of a reaction)

b. Reusable and specific in function

c. Altered by high temperature, pH, and metals (lead, mercury)

2. Recognize how the enzyme-substrate complex model demonstrates the function of enzymes.

Enzymes Objectives continued:3. Recognize a reason why an enzymes

ability to lower activation energy would be beneficial to a living organism

4. Be able to collect, graph, and analyze data relating to enzymes reactions.

5. Explain catalase enzyme action based on the class demo.

Enzymes

A protein that speeds up a chemical reaction

Biological Catalyst

Recall:Inorganic Chemistry

Reactants Catalyst→ ProductsOrganic Chemistry

Substrate Enzyme→ Products

Enzymes activation energy

Energy needed to start a reaction

Enzymes lower the amount of activation energy needed to start a reaction

Enzyme Functions Involved in nearly all metabolic processes.

Speeds up the reactions in digestion of food synthesis of molecules - storage of energy release of energy (aids in breaking molecules into

monomers) Used in transmission of nerve impulses muscle contraction cellular energy

Enzyme Characteristics

Remains unchanged in a reaction Never used up Each enzyme has a specific job

Ex. Amylase – starch enzyme Lactase – lactose enzyme Catalase – hydrogen peroxide enzyme(byproduct

of cell metabolism-poisonous if can’t break down) Sucrase – sucrose enzyme

Enzymes Terms: Substrate – The molecule(s)

that the enzyme acts upon Active Site – the location on

the enzyme where the substrate binds

Theories: Lock and Key theory- specific fit

between the substrate and enzyme

Induced Fit Model- enzyme changes shape a little to fit with the substrate “molds to fit”

Enzymes

Enzymes Coenzyme – a helper, such as vitamins Inhibitor – molecule that blocks or

changes the active site so the substrate cannot bind (2 Types)

Reversible:

Competitive Inhibitors – attaches to active site … competes with substrate for site

1. inhibitor is chemically similar to the substrate

2. Temporary attachment (doesn’t alter active site)

Non-Competitive Inhibitors – binds with the enzyme at a location

other than the active site, altering the shape of the active site

Enzymes

Types of Inhibitors continued Irreversible

Permanently inactivates the enzyme Ex. Poison, exposure to heavy metals such as

mercury and lead

Denaturation – active site of the enzyme is altered,

Causes: temperature, heavy metals, pH

Enzyme review and Negative Feedback

Factors that affect Enzyme Activity pH Temperature Concentration of an enzyme Concentration of substrate Amount of surface area

Enzyme Use Examples: Cheese makers use RENIN (enzyme) to

curdle milk Some laundry detergents contain enzymes

to get rid of soiled spots on clothing Contact Cleaner