The presence of substrate concentration significantly affects the rate of catalysis by enzymes. Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. The relationship between substrate concentration and the rate of enzyme-catalyzed reactions can be described by the Michaelis-Menten equation:v = Vmax * [S] / Km + [S] where v is the reaction rate, Vmax is the maximum reaction rate, [S] is the substrate concentration, and Km is the Michaelis constant, which represents the substrate concentration at which the reaction rate is half of Vmax.Experimental evidence supporting the relationship between substrate concentration and enzyme activity can be observed through the following steps:1. Set up a series of test tubes containing a constant amount of enzyme and varying concentrations of substrate.2. Measure the initial rate of reaction v for each test tube.3. Plot the reaction rate v against the substrate concentration [S] .The resulting graph, called the Michaelis-Menten plot, typically shows the following characteristics:1. At low substrate concentrations, the reaction rate increases linearly with the substrate concentration. This is because the enzyme molecules have many available active sites, and the rate of reaction is directly proportional to the number of substrate molecules that can bind to the enzyme.2. As the substrate concentration increases, the reaction rate begins to level off and approach a maximum value Vmax . This is because the enzyme molecules become saturated with substrate, and the rate of reaction is limited by the number of available enzyme molecules and their turnover rate.3. At very high substrate concentrations, the reaction rate remains constant at Vmax, as the enzyme is working at its maximum capacity.This experimental evidence supports the idea that the presence of substrate concentration affects the rate of catalysis by enzymes. The rate of enzyme-catalyzed reactions increases with increasing substrate concentration until a maximum rate is reached, at which point the enzyme is saturated and cannot process the substrate any faster.