Enzyme concentration in mol/mg - (Oct/05/2010 )

Does anybody know how to obtain enzyme concentration in mol/mg. I need it for calculating Kcat from formula Vmax/Et.
I already have acivity as mol/minute but I don´t know how to change it for mol/mg, Vmax was in mol/min.
Thanks!

If the enzyme has a molecular weight (g/mol or Da), it should be a simple conversion.

The activity is mol/min but it is in terms of moles of substrate converted per minute. I need to know the concentration of enzyme sites in mol/mg so I would have Vmax in moles/min/mg of protein, and Et in mol/mg I could calculate Kcat and have it in units of inverse time.
Do you think I can tranform the activity mol/min taking into account how much mg of protein I have taken to the reaction, and have it in mol/mg? But can I skip min in this case?

Thanks!

specific activity is mol/min/mg protein. this is what you probably need to calculate kcat.