An enzyme is discovered that catalyzes the chemical reaction
SAD --> <-- HAPPY
A team of motivated researchers setout to study the enzyme, which they call happyase. Under a constantenzyme concentration, [E] of 2.0 uM, they studied the relationshipbetween substrate concentration [SAD] and reaction velocityV0. Their data is shown below:
[SAD](uM)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â V0(uMs-1)Â Â Â Â Â Â
20Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 3.4 x 103
40Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 5.4 x 103
60Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 6.6 x 103
80Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 7.4 x 103
Can you determineKcat and Km from the abovedata?
2. While [E] remains 2.0 um and [SAD] = 12 uM, what would thereaction velocity V0 be?
3. In a separate happyase experiment using [E] = 1.0 uM, thereaction velocity, V0, is measured as 3.6 x103 uMs-1. What is the [SAD] used in thisexperiment?
4.The researchers working on happyase discovered that thecompound STRESS is a potent inhibitor of happyase. A kinetics studyof happyase in the presenceof        1 nM STRESS,gives the following data:
[SAD](uM)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â V0(uMs-1)Â Â Â Â Â Â
20Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 1.7 x 103
40Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2.7 x 103
60Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 3.3 x103Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
80Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 3.7 x 103
Which class of inhibitors does STRESSbelong to?
