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# How to calculate Vmax and Km from substrate concentration (enzyme reaction)?

enzyme kinetics Km Vmax enzymekinetics

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Posted 11 April 2018 - 04:24 AM

I would like to calculate Vmax and Km. I have an enzyme reaction, and as the reaction goes by samples were taken at 0,4,8,13,19, and at 28 minute. The substrate concentration (mM) was 12,10,8,6,4,2 respectively. How can I calculate Vmax and Km?

t (min)  S (mM)

0           12

4           10

8           8

13         6

19         4

28         2

t (min) 0;4; 8; 13; 19;28

S (mM)12;10;8; 6; 4;2

Edited by AdamG, 11 April 2018 - 04:28 AM.

### #2 bob1

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Posted 11 April 2018 - 05:47 AM

Plot the values, use the equations for the respective unknowns.  Have a look a Lineweaver-Burke plots...

### #3 mdfenko

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Posted 11 April 2018 - 12:35 PM

from what i see, your data is showing how much substrate is left at each time point. this is not enough to determine max and km. to do that, you have to make a substrate saturation curve by running a series of assays with a range of substrate concentrations.

with that data you can determine the kinetic constants for your enzyme.

keep in mind, if your enzyme is not pure then your constants will not be accurate.

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### #4 mdfenko

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Posted 11 April 2018 - 12:36 PM

see my response in the other forum where this question was asked.

talent does what it can
genius does what it must
i used to do what i got paid to do