What is the Michaelis-Menten equation and what do its parameters mean?

The Michaelis-Menten equation (v = Vmax[S]/(Km + [S])) describes the rate of enzyme-catalyzed reactions as a function of substrate concentration. Vmax is the maximum velocity achieved when all enzyme active sites are saturated with substrate. Km (Michaelis constant) is the substrate concentration at half-maximal velocity and reflects the enzyme's affinity for substrate - lower Km indicates higher affinity. At low [S], the reaction is first-order with respect to substrate; at high [S], it approaches zero-order (rate = Vmax). This model assumes steady-state conditions and a single substrate.