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Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: Prozac on June 14, 2010, 10:27:03 PM

Title: Calculating turn over number of an Enzyme(Kcat)
Post by: Prozac on June 14, 2010, 10:27:03 PM

Any Hints as to how to approach this calculation

Calculate the kcat of Enzyme 2, given the following data. 

Vmax  =  40,000 μmoles/sec, in an assay mixture of 1 mL

Amount of enzyme used in one assay (1 mL)  =  5 μL of a 1 mg/mL solution of enzyme

MW of the enzyme = 50,000 gm/mol

Km of the substrate  =  3 mM



My Approach

Kcat= V_max/E_t


I know my V_max but I dont know how to find E_t

Title: Re: Calculating turn over number of an Enzyme(Kcat)
Post by: Yggdrasil on June 15, 2010, 11:06:35 AM

E_t is the concentration of enzyme in moles/L.  You start with 5µL of a 1mg/mL solution of enzyme, and dilute this in 1mL.  What is the concentration now in terms of mg/mL?  What is that concentration when you convert it to moles/L?