Carbonic Anyhdrase Problem

[dmolson21]

Hi there, I'm new to the forums. I cannot figure out where to go with this problem. Any help would be greatly appreciated. Thanks!



The enzyme carbonic anhydrase is found in erythrocytes, and has a molecular mass of approximately 30000 Da. The hydration reaction catalyzed by this enzyme is reversible, and plays a role in the transport of CO2 from the tissues to the lungs.

H2O + CO2 <-> H2CO3

If 10 micrograms of pure enzyme catalyzes the hydration of 0.30 g of CO2 in 1 minute, at 37 degrees Celsius, under optimal conditions, what is the turnover number (kcat) for carbonic anhydrase?

[admin]

Hello there,
this is a tough question.

I guess you would have to find the # of moles of enzyme using the 300000 Da and the 10micrograms of enzyme?

anybody else?


what is the equation for Kcat?

If you plot enzyme velocity as a function of subtrate concentration, you can fit the data to the Michaelis-Menten equation to determine the Km and Vmax. The Vmax is the maximum enzyme velocity extrapolated out to very high concentrations of substrate. It is expressed in the same units you used to enter your Y values (enzyme activity). Usually it is straightforward to express this (or convert to ) moles/minute/mg of protein.

http://www.graphpad.com/faq/viewfaq.cfm?faq=921

Also how many active sites are there in this enzyme?

cheers