In noncompetitive antagonism, the true statement is:
(A) Km value decrease;.vmaxdecreases (B) no change in vmax;Km value decrease (C) V max decreased; Km value normal (D) Km value increased; V max increased
(C) Answer is c. vmax decreases, km unchangedRef: Harper's Illustrated Biochemistry 30th edn; Page no. 82Noncompetitive inhibitors bind to the enzyme or the enzyme-substrate complex at a site different from the active site, decreasing the activity of the enzyme. Thus, Vmax is decreased.Competitive inhibitionNoncompetitive inhibitionIt is reversed by increasingIrreversiblesubstrate concentration.Excess substrate does not abolishExcess substrate abolishesthe inhibition.inhibition.Km remains the same, but thevmax remains the same, but theapparent vmax is decreased.apparent Km is increased.Inhibitors have no structuralInhibitor will be structuralanalogue of substrate.resemblance to substrate.