Enzymes (Unit 1) Flashcards
How can you increase the rate of a chemical reaction?
Temp, SA, concentration, catalyst
Cellular activity of all living things in controlled through?
Enzymes
Enzymes act as?
Catalyst to accelerate a reaction
Almost all enzymes are?
Proteins (tertiary and quaternary structures)
How are enzymes changed in a reaction?
Are not used up or permanently changed in the process, and do not change the products
Enzyme shape
Each is unique and will determine the reaction the enzyme will catalyze
Substrate
The specific reactant that an enzyme will bind with
Active site
The location on the enzyme where the substrate binds. This site “fits” the substance
Induced Fit Model
While each enzyme fits a specific substance, the enzyme is not rigid. Before the substrate binds, the active site changes its conformation to become even more precise in its ability to bind the substrate
How are enzymes named?
After their substrate. Sucrase breaks down sucrose, proteases break down proteins, lipases break down lipids
What must a reaction overcome in order to move forward?
Energy barrier known as the activation energy
How do enzymes work?
They alter the substrate or its environment which lowers the activation energy required to perform the reaction, so the reaction occurs at a faster rate
Factors Affecting Enzyme Activity
Cofactors and Coenzymes
Enzyme Inhibitors
Allosteric Regulation
Environmental Conditions
Cofactor
A non-protein group that binds to an enzyme and is essential for catalytic function. Are often metals/minerals - iron, copper, zinc, manganese
Coenzyme
Organic molecules that act as cofactors to enzymes. Usually vitamins
Types of Inhibitors
Competitive and Non-competitive
Competitive Inhibitor
Chemicals that resemble an enzyme’s normal substrate and compete with it for the active site preventing the substrate from binding
Non-competitive Inhibitor
Do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which alters the active site so the substrate cannot bind
Allosteric Regulators
Important molecules that function to control chemical activity in a cell. Inhibition or Activation
Allosteric Inhibition
When the product of the reaction is in excess, an inhibitor will bind to the enzyme, changing its shape and stopping enzyme activity and production of the product
Allosteric Activation
When the product is at low levels, an activator will bind to the enzyme, changing its shape to allow the substrate to bind to the enzyme, increasing the rate of reaction
Environmental Conditions
Temperature, pH, Ionic Concentration
Temperature
Extreme temperatures are very dangerous
pH
Most like 6-8, or near neutral. pH outside of the normal range causes enzymes to lose their structure. Optimal pH range may change
Ionic Concentration (salt ions)
Interferes with protein folding changing the shape of the enzyme
