Controlling EnzymesEnzymes sometimes need to be controlled. An organism can create its own molecules to slow down and stop the activity of enzymes and proteins. At other times, enzymes can by controlled by poisons and contaminants, such as herbicides. So, what affects enzyme activity?
Temperature: That's a good one. Proteins change shape as temperatures change. Because so much of an enzyme's activity is based on its shape, temperature changes can mess up the process and the enzyme won't work. High enough temperatures will cause the enzyme to denature and have its structure start to break up.
Activators: Sometimes you need an enzyme to work faster. Your body can then create activators. At other times, you might eat something that plays the role of an activator. Activators make enzymes work harder and faster. If you're running in a race and you need more energy, get those enzymes to work! Hormones can trigger responses that activate enzymes.
pH Levels: The acidity of the environment changes the shape of proteins in the same way that temperature does. Do you remember that pH is a measure of acidity? An increased acidity near an enzyme can cause its shape to change. Those polar and nonpolar amino acids start to twist. If there is enough of a change, the protein could unravel and become totally ineffective.
Inhibitors: These are the opposite of activators. Inhibitors either slow down or stop the activity of an enzyme. They often bond to the protein, changing the overall shape of the enzyme. Remember, when the shape changes, the enzyme will not work the same way. A nasty example of an inhibitor is snake venom or maybe nerve gas from World War I.
Enzyme Molecules as Nanomotors (American Chem Society Video)