Enzyme Kinetics: Understanding Basic Concepts and Relevant Equations

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In summary, the conversation discusses a biology problem related to the Michaelis-Menten equation. The equations and notes provided are relevant for deriving the equation and solving a part of the problem. The conversation also mentions the option of using an image file instead of a powerpoint file. For part (a), the solution involves using the steady state assumption. For part (b), the solution involves using a mathematical approach to find the two parameters in the equation. The conversation also mentions that knowledge of kinetics and equilibrium chemistry may be helpful.
  • #1
tunabeast
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Homework Statement



Hi, having not studied biology I'm struggling to get to grasps with what are probably basic concepts. Looking through the notes i have i was just wondering if the equations/derivations i'v attached are relevant, and if so how. A link to the powerpoint file can be found here http://www.megaupload.com/?d=V3DVK5JX [Broken]. Here is the question I'm stuck on


http://i1.tinypic.com/6xizsyx.jpg
 
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  • #2
tunabeast said:

Homework Statement



Hi, having not studied biology I'm struggling to get to grasps with what are probably basic concepts. Looking through the notes i have i was just wondering if the equations/derivations i'v attached are relevant, and if so how. A link to the powerpoint file can be found here http://www.megaupload.com/?d=V3DVK5JX [Broken]. Here is the question I'm stuck onhttp://i1.tinypic.com/6xizsyx.jpg
I haven't actually downloaded and looked at the ppt file - I'm a little nervous about things like that. I'd probably be more likely to look at an image file uploaded to an image hosting site, but maybe others here are more daring. The best option would be if you just posted the work here, using the on-site [itex]\LaTeX[/itex] capability.

For (a), it looks like you are asked to derive the Michaelis-Menten equation using d[E]/dt ~ d[ES]/dt -> very small (i.e., steady state assumption).

For (b), you must simply extract the 2 parameters in the MM equation from the dataset. You can do this by plotting the dataset and doing a 2-parameter fit with the MM equation. Or just use two far away data points from the set and solve for Km and max. rate, then check that this gives you accurate predictions for the other rates in the set.

PS: You need essentially no knowledge of biology for this, but kinetics and equilibrium chemistry are probably a pre-requisite.
 
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  • #3
Thanks very much for the information. I completely understand about the download link, and i'v now attached a PDF file of the presentation. I think the answer to part a may well be on the second page. However unfortunately I'm still at a dead end on (b). Would it require plotting a graph? If so what kind and what would i be trying to interpret from the graph. Thanks again
 

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  • Basic enzyme kinetics.pdf
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  • #4
Your solution to part (a) is spot on!

Part (b) is just a little bit of math - you can find the answers the rigorous way (graphically, but probably unnecessary) or the easy way.

1. Take your final equation for [itex]\nu[/itex] vs. .
2. Notice that the table gives you vs. [itex]\nu[/itex]
3. Pick any two well-separated pairs from the table, say (0.00005, 0.000625) & (0.0003, 0.00167)
4. Plug each pair of values into the equation; you should end up with 2 equations in 2 unknowns (Km and v(max)).
5. Solve for these unknowns.
6. With the values you get for Km and v(max), plug in the other values of into the equation and check that you get answers pretty close to the corresponding values of [itex]\nu[/itex] in the table.
 

1. What is enzyme kinetics?

Enzyme kinetics is the study of the rate at which enzymes catalyze biochemical reactions. It involves analyzing the factors that affect enzyme activity, such as substrate concentration and enzyme concentration, and understanding the underlying mechanisms of enzyme catalysis.

2. How do enzymes work?

Enzymes are biological molecules that act as catalysts, speeding up the rate of biochemical reactions. They work by binding to specific substrates, which allows them to lower the activation energy required for the reaction to occur. This makes the reaction happen more quickly and efficiently.

3. What is the Michaelis-Menten equation?

The Michaelis-Menten equation is a mathematical model used to describe the relationship between the rate of an enzyme-catalyzed reaction and the substrate concentration. It takes into account the maximum reaction rate (Vmax) and the Michaelis constant (Km), which is a measure of how tightly the enzyme and substrate are bound.

4. How does temperature affect enzyme kinetics?

Temperature can greatly impact enzyme kinetics. As temperature increases, the rate of enzyme-catalyzed reactions also increases, up to a certain point. This is because higher temperatures provide more energy for the molecules to move and collide, increasing the chances of successful enzyme-substrate interactions. However, excessively high temperatures can denature enzymes and decrease their activity.

5. What are some common inhibitors of enzyme activity?

Inhibitors are molecules that can bind to enzymes and decrease their activity. Common inhibitors include competitive inhibitors, which bind to the active site of the enzyme and compete with the substrate, and noncompetitive inhibitors, which bind to a different site on the enzyme and change its shape, making it less effective. Other inhibitors include feedback inhibitors, which regulate enzyme activity in metabolic pathways, and irreversible inhibitors, which permanently inactivate enzymes.

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