Enzymes Flashcards
Lock and key hypothesis
Where the substrate is complementary to the active site on an enzyme
All atoms automatically form temporary strain on bonds
Induced fit
Active site changes shape slightly to fit substate
Bonds are weak at first but activates a strengthening bond
Puts strain on substrate
Describe process of enzyme action
Substrate binds to active to form;
Enzyme-substrate complex
Reaction occurs
Product formed in enzyme-product complex
Types of reactions
Catabolic- enzyme breaks down substrate into multiple products
Anabolic; enzyme combines substates to form final product
Types of enzymes and examples
Intracellular; within cells.
Eg DNA polymerase and ligase
Extracellular: work outside cells
Eg digestive enzymes: protease and lipase
Difference between co-factor, co-enzyme and prosthetic group.
Co-factors are non-amino part of a protein that helps the function of the protein. They bind to an enzyme’s allosteric site, permanently or temporarily.
Co-enzymes are a type of co-factor that are organic
Prosthetic groups are a type of co-factor that are inorganic or organic and usually bound to the protein for a long time.
Example of co-factors
Cl- ion
Activation of amylase
Bind loosely to activate enzyme
Co enzyme example
Vitamins
Vitamin B3 in NAD and NAPD
Enzyme activity with decomposition hydrogen peroxide
Catalase enzyme used
Breaks H202 to
H20 and O2
2H2O2—— 2H2O + O2
Digestive enzymes
Extracellular enzymes
Hydrolyse macromolecules
Eg amylase: starch into glucose
Pepsin; protein into amino acids
Function and structure of enzymes
Catalyses reactions by reducing activation energy
Globular protein with active site
Hydrophobic active site
Hydrophilic outside
Prosthetic groups
Non-amino acid Permanent feature of the protein
Eg Zn2+ in carbonic anhydrase
In metabolism of CO2
Factors that affect enzyme rate of reaction
Temperature
pH concentration
Substrate concentration
Enzyme concentration
Temperature factor
Low temps mean substrates have less kinetic energy and move slower = less collision with enzyme
Optimum; higher kinetic energy and substrate are at quickest with max collisions
Denature; above optimum breaks bonds on active site and changes its shape
pH factor
Low;
The more H+ ions, the less R groups interact as H+ interact with polar and charged r groups
High;
Less h+ ions= more interaction
Optimum pH- all interactions in tact and completely complementary
