Factors that Affect Enzyme Rates How to understand and analyze enzyme graphs

Enzymes are Picky! All enzymes have a RANGE of temperature and pH that they work best in. Not all enzymes work the best at the same temperature and pH levels. Example- Most enzymes in our body work best at a temperature of 40 C. But they still work pretty well from about 39-41 C.

Human Body Enzyme Graph At about 40 C, you can see that the enzyme works at the OPTIMAL level. What is happening to the enzyme at a temperature of 50 C?

Enzyme Rates Based on pH The graph on the left shows the rate of enzyme activity for 3 different enzymes based on pH levels. Which color graph would most likely represent an enzyme that works to break down food in the stomach?

Enzyme Rate Based on Enzyme Concentration The more enzymes available, the faster a reaction can take place. However, at some point there will be so many enzymes and not enough substrate for the reaction to continue to increase speed. We call this point the SATURATION POINT.

Typical Graph of Increasing Enzyme Concentration

Enzyme Activity Based on Substrate Concentration The more substrate available, the faster a reaction can take place. However, an enzyme can only work so fast (think of it as a top speed) and the substrates will have to wait around so the reaction rate levels off. We also call this the SATURATION POINT.