Help calculating Kcat

Hi,

Here is some information. I don't know what is necesary so if more information is needed, please say so and I will try to provide more info.

Vmax = 49.83  ( µmol * mg )/min
Km = 7.827 µM.

I know  Kcat= Vmax / [Enzyme]

I have gotten here: 49.83 (µmol / min*mg) * ((1 min)/(60 sec)) * (1/[Enzyme])

- I can't figure out the concentration of the enzyme in a way that will cancel the units and leave me with s-1 (units I need for Kcat).
- More info: The concentration of enzyme used was 2 mg/ml and 15 uL was used in each buffer solution to create the kinetics curve.

Thanks for looking at my post!