Assignment 4


1 .		The Role of Acarbose as an Invertase Inhibitor experiment is designed to help you determine whether acarbose functions as a competitive or noncompetitive inhibitor of invertase. Determine V_max and K_M for the uninhibited and inhibited studies, then answer the following questions. Compare your data from the inhibited reactions to your data from the uninhibited experiments. What did you find? Explain what happened to invertase activity as you increased [S]. Why did this occur? What happened to V_max in the presence of the inhibitor? What happened to K_M? If either V_max or K_M changed, explain why. Based on these results and what you already know about inhibitors of enzyme activity, is this inhibitor functioning as a competitive inhibitor or a noncompetitive inhibitor? How do you know? Explain your answers below.

2 .		To investigate how DRI inhibitor B inhibits invertase, carry out the same sets of experiments, both uninhibited and inhibited, with DRI inhibitor B that you set up for acarbose. For inhibited measurements, set DRI inhibitor B to 25 mM. Compare your data from the inhibited reactions to your data from the uninhibited experiments. What did you find? Explain what happened to invertase activity as you increased [S]. Why did this occur? What happened to V_max in the presence of the inhibitor? What happened to K_M? If either V_max or K_M changed, explain why. Based on these results and what you already know about inhibitors of enzyme activity, is this inhibitor functioning as a competitive inhibitor or a noncompetitive inhibitor? How do you know? Explain your answers. Compare and contrast what happened as you increased [S] with acarbose to what happened with DRI inhibitor B. Were the results the same or different? If the effect of [S] on invertase was different in the presence of each inhibitor, explain why.