Final answer:
The reaction rate of an enzymatic reaction increases with substrate concentration until enzyme saturation occurs, at which point the rate remains constant despite further substrate increases. This results in a hyperbolic curve when plotted on a graph.
Step-by-step explanation:
The reaction rate or velocity of an enzymatic reaction varies with substrate concentration in a characteristic way. Initially, as the substrate concentration increases, the reaction rate increases as well. This is because more substrate molecules are available to collide with enzyme molecules, resulting in more frequent enzyme-substrate complexes and thus a higher reaction velocity. However, this increase continues only until the enzyme becomes saturated with substrate. At saturation, all active sites of the enzyme molecules are occupied with substrate, so adding more substrate does not increase the reaction rate further. This relationship between substrate concentration and reaction rate produces a hyperbolic curve when graphed, representative of many enzymatic reactions. On a graph with substrate concentration on the x-axis and reaction rate on the y-axis, the initial increase in rate is steep with low levels of substrate; however, this increase in rate levels off as substrate concentration continues to rise, reflecting the saturation point where the maximum rate has been achieved.
Understanding this enzyme kinetics is crucial in fields like biochemistry and medicine, where enzyme behavior influences drug efficacy and metabolic pathways. The initial reaction rates (vo) can be estimated by plotting the slope of the first few time points on a graph. Moreover, this enzyme behavior follows Michaelis-Menten kinetics, a model that helps scientists and students understand these reactions quantitatively.