how to calculate Kcat value of enzyme

Dr Engelbert Buxbaum via (by engelbert_buxbaum from
Wed Jan 16 12:07:10 EST 2008

Am 10.12.2007, 07:28 Uhr, schrieb <jrsimkhada from>:

> Good evening
> 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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