Enzymes Flashcards
What is the role of a catalyst in a chemical reaction?
To increase the rate at which a reaction reaches equilibrium by binding to substrate and stabilising the transition state
Transition state usually has greatest free energy
Enzymes reduce activation energy by providing alternate route
Why are co-factors and co-enzymes important?
Many enzymes need them in order to function
What is an active site?
Crevice in protein containing amino acids for highly specific interactions and amino acids essential for catalytic activity
Why do temperature and pH affect enzyme activity?
Conformation changed by changing bonds when temperature/pH changes
What is an isozyme?
Enzymes which catalyse the same reaction but have different properties, structure, and amino acid sequence
Why are enzymes important?
Act as catalysts and ensure the essential metabolic reactions within the body occur at a rate which will sustain life
Are all enzymes made of protein?
No, most are, but some made of RNA (ribozymes)
How much do enzymes increase rate of reaction?
Up to 10^20 times faster
Can some enzymes distinguish between stereoisomers of their substrate?
Yes, some can
What are co-factors?
Metal ions which create co-ordination centre within enzyme
What is a metalloprotein?
Enzyme with metallic co-factor
What are coenzymes?
Organic molecules which briefly associate with enzyme
Can change charge and structure during reaction, regenerated for next reaction
What is a prosthetic group?
Tightly bound coenzyme
What is an enzyme with no co-factor called?
apoenzyme
What is an enzyme with a co-factor called?
holoenzyme
