Final answer:
The x-axis in the Eadie–Hofstee plot represents the ratio of initial reaction velocity to substrate concentration (v/[S]), which is used to estimate enzymatic parameters such as Vmax and Km.
Step-by-step explanation:
In the Eadie–Hofstee plot, the x-axis represents v/[S], which is the initial reaction velocity (v) divided by the substrate concentration ([S]). This kind of plot is a transformation of the Michaelis-Menten equation used to analyze the kinetics of enzyme-catalyzed reactions. It allows researchers to estimate the maximum reaction velocity (Vmax) and the Michaelis constant (Km) from the slope and intercept of the plot, respectively.
The Michaelis-Menten equation suggests that as [S] increases, the reaction velocity (v) also increases, up until a point where all enzyme active sites are saturated with substrate, and the reaction velocity reaches its maximum rate, Vmax. The substrate concentration at which the reaction velocity is half of Vmax is defined as Km. The Eadie-Hofstee plot is a linear transformation that can simplify the determination of these parameters by avoiding the need for nonlinear regression.