Although the MWC theory describing binding to a multisite protein is quite complicated, we...

Although the MWC theory describing binding to a multisite protein is quite complicated, we can easily derive equations for a simple case. Assume a dimeric enzyme, with two active sites and two conformational states: T and R. For simplicity, assume that the R state can bind one or two molecules of substrate, but the T state cannot bind. We then have the equations

The factor 2 appears because there are two equivalent sites on each R to bind S.

(a) From this information, show that the fraction of sites occupied at substrate concentration [S] is

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 (b) Picking a large value of L (say 105), and with K = 10−6 M, show that a sigmoidal curve is obtained for v/ Vmax versus [S].