Question

The figure given below show three velocity substrate concentration curves for an enzyme reaction. What do the curves a, b and c depict respectively?

• A. a- Normal enzyme reaction
  b- Competitive inhibition
  c- Non-competitive inhibition
• B. a- Enzyme with an allosteric modulator addedb- Normal enzyme activity
  c- Competitive inhibition
• C. a- Enyzme with an allosteric stimulator
  b- Competitive inhibitor added
  c- Normal enzyme reaction
• D. a- Normal enzyme reaction
  b- Non-competitive inhibitor added
  c- Allosteric inhibitor added

Answer 1

The correct option is A a- Normal enzyme reaction

b- Competitive inhibition
c- Non-competitive inhibition
The effect of a competitive inhibitor is reversed by increasing substrate concentration. At a sufficiently high substrate concentration, the reaction velocity reaches the V${}_{max}$ observed in the absence of inhibitor, whereas non-competitive inhibitor decreases the V${}_{max}$ of the reaction, i.e., it can not be overcome by increase in substrate concentration.