Enzymes & enzyme inhibition Flashcards
What are inhibitors?
Substances that bind to an enzyme and reduce the rate of its activity (prevents an ESC forming)
What is an ESC?
Enzyme-substrate complex
What is a competitive inhibitor?
- completes with the substrate to bind with the active site.
- inhibition depends on concentration.
- prevents ESC from forming.
- usually reversible.
What is a non-competitive inhibitor?
Bonds to an alternate site (allosteric site) of an enzyme which alters the tertiary structure (denatured) and prevents ESC from forming.
What are enzymes?
biological catalysts that speed up the rat or metabolic reactions
- are not used up by reactions (reusable)
- all are globular so soluble in water
- catalyse wide range of intracellular and extracellular reactions
What are examples of intracellular reactions?
inside cells- protein synthesis, aerobic respiration, anaerobic respiration
What are examples of extracellular reactions?
outside cells- hydrolysis in digestion, blood clotting
What bonds are in the primary structure?
Peptide bonds between amino acids
What bonds are in the secondary structure?
hydrogen bonds hold together the alpha helix or beta pleated sheet
What bonds are on the tertiary structure?
- hydrogen
- ionic
- disulphide
What bonds are in the quaternary structure
- hydrogen
- ionic
- disulphide
How does changing the pH affect an enzyme controlled reaction?
- Just above/ below optimum pH: induced fit is slightly less effective so slightly fewer ESC– rate decreases
- optimum pH: ESC forming quickly so rate increased
- pH is too high/low: hydrogen and ionic bonds break so tertiary structure is disrupted and active site changes shape– substrate can not fit (enzyme is denatured)
