NTA Abhyas NEET2020ChemistryBiomoleculesPractice
In an enzyme-mediated reaction, Km value is:
Options
- AThe substrate concentration at which the velocity of the chemical reaction is maximum
- BThe substrate concentration at which the velocity of the chemical reaction is half its maximum value
- CThe velocity of the chemical reaction at which the substrate concentration is maximum
- DThe velocity of the chemical reaction at which the substrate concentration is half its maximum value
Correct answer
B. The substrate concentration at which the velocity of the chemical reaction is half its maximum value
Step-by-step solution
Km (Michaelis Menten Constant) is the substrate concentration at which the chemical reaction attains half of its maximum velocity. With the increase in concentration of substrate, the enzymatic velocity also increases. At a certain value all the active site of the enzyme molecules are saturated. Increase in substrate concentration does not increase the velocity of the enzymatic reaction. Higher is the affinity of an enzyme for a substrate, lower is the Km value. Km value lies in between 10 - 1 to 10 - 6 M . Km valu