DISCUSSION
The Effect of substrate Concentration
As the concentration of substrate increases, the rate of reaction also increases until the point saturation occurs. It means as you increase the concentration, rate keeps increasing and then one point comes when the maximum rate is achieved and there is no free enzyme to bind with substrate and all the active sites of enzyme are bound to the substrate. So after that point, increasing the concentration wont have any effect. What is the maximum for each enzyme is usually given by Km value (michealis menten graph or the other one called sumting like Lineweaver burke plot). The Km value is the rate constant or it can be explained as how much substrate concentration is required by an enzyme to reach to the half of maximum rate or velocity of enzyme. Each enzyme has different Km values. So I hope that answers ur quesiton- wherever the Vmax occurs and it intersects the curve drawn for substrate concentraion and velocity (or rate of reaction), that point is the saturation point or maximum substrate concentration to have maximum rate of the reaction.
Based on our experiment, we got negative value for rate of hydrolysis (V). According to the theory we are not supposed to get negative value for (V). In other words it states that, when the substrate concentration change and while enzyme concentration is keeps constant, the rate of reaction will increase. This is because there are a few error that occurred during we ran the experiment.