Determining Enzyme Kinetics

2 posts / 0 new
Last post
Tara-linth's picture
Determining Enzyme Kinetics

 Hi everyone!

I seem to be in a bit of a pickle and I was really hoping that somebody could help me please. 
Recently we did an experiment wherewe had to determine the activity and kinetic parameters of a certain enzyme. For the second part, we had to draw a Michealis Menten plot. This is where I got a bit lost

I constructed graphs for Absorbance vs Time, and used their slopes in the Beer Lambert law in order to get concentration per time. From here I need touse these to plot a Michealis menten graph but I am not sure how. Should I use Activity (U/ml) , total activity (U) or specific activity (U/mg) to plot the graph?

Thank you

Chin Fen Teo
Chin Fen Teo's picture


To plot Michealis Menten, the x-axis is substrate concentration and y-axis is velocity,

Hence, you need to calculate your enzyme velocity (rate at which product is formed). If you have a standard curve where you know the absorbance of your product, you should be able to back calculate your enzyme velocity from the Abs vs time reading. And then, use the information you obtain to fill in your y-axis.

Good luck,