how to calculate Kcat value of enzyme
(by analia_alet from intech.gov.ar)
Mon Jan 21 09:35:46 EST 2008
Hi, kcat = Vmax/Km, where Vmax could be expressed in mnol/(mg min) and Km in
uM, so kcat is expressed in min-1
one good book explaining all this is
Enzyme Kinetics: Behavior and Analysis of Rapid Equilibrium and Steady-State
Enzyme Systems (Wiley Classics Library)by Irwin H. Segel (Author)
> molecular weight of enzyme is 60 kDa and I took 4 ug of it in each
> reaction. Vmax and km values were obtained as 1.24 mmole/min/mg
> protein and mM. so how could i calculate Kcat value of the enzyme ?
> I will be very grateful for your kind cooperation.
From your data you can first calcualte the molar amount of enzyme per
reaction. Then re-express the velocity as mmole/min/mmole = 1/min, convert
min to sec and you have the turnover number in 1/s = kat. If you have
problems with any of that, ask your instructor to go through the
calculation with you.
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