Enzyme Flashcards
All enzymes are proteins except a small group of catalytic RNA molecules called
Ribozymes
Some enzyme require non-protein molecules called ___ for activity
Cofactors
Transient carriers of specific functional group covalently bound to an enzyme
Coenzyme
Coenzymes are inrganic cofactors
False. Organic
Protein or inactive part of enzyme
Apoenzyme
Enzyme with the required cofactors for activity is called ____
Holoenzyme
Classification of enzyme involving substrstes in a redox reactions
Oxireductases
Classification of enzyme involving transfer of functional group between two substrates
Transferases
Classification of enzyme involving hydrolysis with the addition of water
Hydrolases
Classification of enzyme involving addition of a group to a double bond or elimination of a group to create a double bond without hydrolysis
Lyases
Classification of enzyme involving transfer of groups withing substrates to yield isomeric forms
Isomerases
Classification of enzyme involving formation of bonds by condensation reactions coupled to cleavage of ATP or similar cofactor
Ligases
Classification of enzyme involving movement of ions or molecules across membranes or their separation within membranes
Translocases
Substrate binding occurs in a pocket on the enzymes called _____
Active site
Enzymes increases the activation energy for a reaction, enhancing the reaction rate. True or false
False. Lowers the activation energy
The _____ suggests that the substrate possess specific complementary geometric shapes that fit exactly into one another. Demonstrates sensitivity to pH and temperature.
Lock and key model, Emil Fischer
_____ debunks the lock and key model and suggests that enzymes undergo conformational changes during catalysis.b
Induced fit model, Daniel Koshland
Accounts for the exquisite specificity of enzymesbfor their substrates
Binding energy
Condition wherein the rate at which the ES complex forms balances the rate at which it reacts.
Steady state
Very useful in distinguishing between certain types of enzymatic reaction mechanisms snd in analyzing enzyme inhibition.
Lineweaver-burk plot
Rate at which the enzyme catalyzed reaction has fully saturated active site.
Vmax
Inhibitors that compete with the substrate by binding reversibly to the active site.
Competitive Inhibitors
Inhibitors that bind only to the ES Complex, at a site distinct from the active site
Uncompetitive Inhibitors
Inhibitors that binds to either E or ES
Mixed Inhibitors
An inhibitor that binds permanently to an active site by forming a covalent bond or a very stable noncovalent interaction
Irreversible inhibition
Type of inhibition wherein the end product of a pathway inhibits the first enzyme of that pathway. It also helps maintain homeostasis
Feedback inhibition
Enzymes that exhibit increased or decreased catalytic activity in response to certain signals
Regulatory enzymes
Enzymes that functions through reversible, noncovalent, binding of modulators or effectors
Allosteric enzymes
