Michaelis Constant

#Biochemistry

$\displaystyle K_{m}=\frac{k_{-1}+k_{2}}{k_{1}}$

• Parameter in the Michaelis-Menten equation that correlates with how quickly an enzyme reaches $\displaystyle v_{\text{max}}$ when increasing $\displaystyle [S]$. Lower $\displaystyle K_{m}$ means higher enzyme binding affinity for the substrate
• Actual definition is the $\displaystyle [S]$ at which $\displaystyle \frac{v_{\text{max}}}{2}$ is reached
• Can also be thought of as how much $\displaystyle \ce{ES}$ tends to dissociate
• $\displaystyle k_{-1}+k_{2}$ corresponds to the efflux of ES into E + S and E + P whereas $\displaystyle k_{1}$ corresponds to the influx from E + S to form ES