Botany - Biomolecules Question with Solution | TestHub

The catalytic efficiency of two different enzymes can be compared by comparing their ${\mathrm{K}}_{\mathrm{m}}$ value or Michaelis Menten constant. The Michaelis constant is the substrate concentration at which the reaction rate is at half-maximum. The ${\mathrm{K}}_{\mathrm{m}}$ describes the affinity of enzyme for a substrate molecule. Greater the affinity lower is the ${\mathrm{K}}_{\mathrm{m}}$ value and sooner the ${\mathrm{V}}_{\max }$ can be attained and vice versa. Related Theory $K_m$ is the concentration of substrate which permits the enzyme to achieve half Vmax. An enzyme with a high $K_m$ has a low affinity for its substrate, and requires a greater concentration of substrate to achieve Vmax. The relationship is defined by the MichaelisMenten equation: $$v=V_{\max }/\left(I+\left(K_m/[S]\right)\right)$$ The Lineweaver-Burk double reciprocal plot rearranges the Michaelis-Menten equation as: $$1/v=1/V_{\max }+K_m/V_{\max }\times 1/[S]$$ Plotting 1/v against 1/[S] give a straight line: where: $y$ intercept $=1/V_{\max }$ gradient $=K_m/V_{\max }$ $x$ intercept $=-1/K_m$