Enzyme specificity is given by -

Ans. is "a' i.e., Km "The of an enzyme is the concentration of the substrate that enables the enzyme to function at half maximum activity and is therefore a measure of the specificity of a substrate for the enzyme"___________Clinical biochemistryo Actually enzyme specificity is not measured by Km alone.o It is measured by the ratio Kcat/Km which is a second order rate constant for the reaction between substrate and free enzyme.o This ratio is important, for it provides a direct measure of enzyme efficiency and specificity,o Note : Kcat is turnover number and measures the rate of the catalytic process.