Biochem test 2 Flashcards

oxioreductase

transferase

hydrolase

Lyase

Isomerase

Ligase

transient chemical species formed and decayed in reactions

step with highest activation energy in a reaction

• rate is constant and does not depend on the amount of substance
• rate depends on presence of catalysts
• Enzyme-catalyzed reactions exhibit zero-order kinetics when the reactant concentrations are so high that the enzyme is completely saturated with reactant molecules

• Rate is proportional with the amount of substrate present
• Description of a reaction whose rate depends on the first power of the concentration of a single reactant

• Has undergone modifications but is still the basic model for non-allosteric enzymes.
• KM - Inverse measure of the affinity of the enzyme for the substrate; Lower the KM, the higher the affinity
• Km=michaelis constant
• Enzymes can only process so fast.
  • At low substrate → rate increases almost linearly
  • At high substrate → enzyme becomes saturated, rate levels off
  • v: reaction rate
• [S]: substrate concentration
• Vmax⁡: maximum rate (when enzyme is saturated)
• Km​: Michaelis constant (substrate concentration at half Vmax⁡)

• double reciprocal plot of enzyme kinetics

x int= -1/Km

y int =1/Vmax

slope=Km/Vmax

• Inhibitor does not interfere with substrate binding

–Value of Vmax decreases, and value of KM remains the same

• Increasing substrate concentration cannot overcome noncompetitive inhibition

–Inhibitor and substrate are not competing for the same site