GI - Week 1 Flashcards
enzymes lectures
Michealis-Menton Kinetics: What does it say about reactions with a low substrate concentration?
- what type of reaction-graph does this give us?
the substrate concentration is the factor limiting the rate of reaction
first order
Michealis-Menton Kinetics:What does it say about reactions with a high substrate concentration?
- what type of reaction-graph does this give you?
the enzymes are working at maximum capacity so the rate of reaction is limited by the ability of the enzyme to turn over the substrate
zero order
Michealis-Menton Kinetics: What does Vmax represent?
the theoretical saturation point
Michealis-Menton Kinetics: What does Kcat mean?
the maximum number of substrate molecules converted to product by one enzyme per unit time
Michealis-Menton Kinetics: Km is the rate constant. What does Km represent?
the affinity of the enzyme for the substrate
Enzyme Inhibitors: State 2 DRUG examples and what they inhibit
caprofen is a COX-2 inhibitor
penicillin inhibits bacterial transpeptidase
Enzyme Inhibitors: What do these generally do?
- what 2 types are there?
- is the binding reversible?
they bind to enzymes and decrease their activity
competitive and non-competitive
can be reversible or irreversible
Enzyme Inhibitors: How do competitive inhibitors work? 2
- is it reversible?
they have a similar shape to the substrate
so compete with the substrate for the active site
yes
Enzyme Inhibitors: Give a clinical example of a competitive inhibitor
- how does it work?
ACE inhibitors like captopril
they have a different structure to teptropride but bind to the same sites on the active site of the ACE enzyme
Enzyme Inhibitors: How do Non-competetive inhibitors work? 3
- is this reversible?
they bind to the enzyme at an allosteric site
this causes changes to the 3d structure of the enzyme
the substrate no longer fits the active site
no
Enzyme Inhibitors: Why is non-competitive inhibition not reversible? 2
- give a clinical example
it forms a covalent bond to the amino acid
this permanently inactivates the enzyme
aspirin inactivates COX1 AND COX 2 enzymes
Define Enzyme
enzymes are proteins that function by accelerating chemical reactions in biological systems
How do enzymes increase the rate of reaction?
they lower the activation energy needed for the reaction to take place
Describe the forces happening during substrate binding to an enzyme
multiple weak non-covalent interactions occur
State the 2 types of enzyme-substrate reaction models
lock and key
induced fit
