So I have two substrates for one enzyme and I measured the product formation-> michaelis menten kinetics. The Vmax for both substrates is the same, the Km however is higher on substrate number 2. What can I conclude from this in terms of enzyme-substrate interaction?


closed as off-topic by The Last Word, De Novo, David, kmm, theforestecologist Nov 17 '18 at 5:18

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  • $\begingroup$ Homework questions are discouraged on here. $\endgroup$ – The Last Word Nov 14 '18 at 23:01

The situation you described is entirely normal. $V_{max}$ is the same, so when described with a graph of initial reaction rate vs. substrate concentration, both curves will asymptotically approach the same maximum level. $K_M$ is higher in one than the other, so the exact shape of the curve as it goes from 0 to $V_{max}$ is different. As you may know, you can interpret $K_M$ as the substrate concentration that causes the initial reaction rate to be half of $V_{max}$. This means the substrate with the higher $K_M$ will have a shallower first half of the curve.

You can read more about these parameters and initial enzyme kinetics in Berg biochemistry or at khanacademy.

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    $\begingroup$ This does not answer my question of enzyme-substrate interaction though :), thank you for the effort nonetheless. $\endgroup$ – Flip Nov 14 '18 at 22:00
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    $\begingroup$ @Flip you'll have to clarify your question then. $\endgroup$ – De Novo Nov 14 '18 at 22:52
  • $\begingroup$ @DeNovo : Seems like the question of OP is to describe the enzyme substrate interaction when Vmax is same and Km is different. $\endgroup$ – user237650 Nov 16 '18 at 4:40
  • $\begingroup$ @user237650 that still needs clarification. As I understand the words of that question, this answers it (the difference between the way those two substrates interact with the enzyme is that the initial reaction rate increases more gradually for the second substrate) but there must be something else the OP is looking for. $\endgroup$ – De Novo Nov 16 '18 at 5:01

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