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Unformatted text preview: When [ET] = 0.1 nM, determine the value of each of the following parameters:
(a) Km; (b) Vmax; (c) Turnover number (kcat); and, (d) Initial velocity when [S]0 = 20 µM. (a) In the kinetic scheme shown above, Km = (k2 + k3) / k1 = (105 s-1 + 102 s-1) / 109 M-1 s-1 =
1.001 x 105 s-1 / 109 M-1 s-1 = 1.001 x 10-4 M = 0.1 mM
(b) In the kinetic scheme shown above, Vmax = k3[ET] = 102 s-1 (10-10 M) = 10-8 M s-1 = 10 nmole L-1 s-1
(c) In the kinetic scheme shown above, kcat = Vmax / [ET]; and, kcat = k3 = 102 s-1 =
100 molecules of S converted to product per second per enzyme molecule
(d) Since we have determined Km and Vmax, and are given a starting substrate concentration, we can use
the Michaelis-Menten equation to determine the initial velocity at that [S] value:
v0= Vmax [S] / (Km + [S]) = 10-8 M s-1 (2 x 10-5 M) / (1....
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This note was uploaded on 03/15/2014 for the course MCB 102 taught by Professor Staff during the Fall '08 term at University of California, Berkeley.
- Fall '08