Enzymes speed up chemical reactions by lowering the activation energy needed. They do this by attaching to active sites on proteins, allowing the proteins to vibrate and contact substrates faster than without enzymes. Enzymes work best within an optimal pH and temperature range, as they can denature outside of this range. The document describes an experiment testing the effect of enzyme concentration on reaction rate, finding that high enzyme concentration led to rapid substrate breakdown initially, slowing over time as the solution became saturated, while low enzyme concentration showed slower initial but similar final substrate breakdown.

1. Francisco Fuster<br />April 1, 2011<br />Enzyme kinetics:<br /> The purpose of this lab is to understand how enzymes catalyze, or speed up reactions by using less activation energy. What they do is that they attach themselves to an active site that exists as an indentation in a specific protein. This protein will then perform faster because it will vibrate and come into contact with its task a lot faster than it would without the enzyme. Enzyme, however have an optimal range of pH and temperature in which they are working at their maximum level. We have to remember that enzymes are normally proteins, so they can denature if they are not in those optimal levels. Other enzymes are nucleic acids which may degrade with a change in temperature and pH. What we did was, test the speed of the enzyme’s work. We added a substrate to a test tube that later on, would be broken down. One had a high concentration of enzymes and the other had a low concentration. As the substrate was being broken down it emitted a yellow color. In the high concentration enzyme test tube, we saw that during the first 2 minutes, the concentration of the substrate increased rapidly because it had a high concentration of the enzyme. However after 8 minutes the concentration of the substrate didn’t change much when compared to the first 2 minutes. This happened because the solution later became saturated with the substrate. In the other test tube containing low concentration enzyme, on the first 2 minutes the concentration of the substrate didn’t increase as rapidly as the high concentration because we had a small amount of the enzyme present in the solution. However the final absorbance values of the low and high concentration enzyme were almost the same, because we had a limited amount of substrate in the solution. <br />