2) The initial rate for an enzyme-catalyzed reaction has been determined at a number of substrate...

2) The initial rate for an enzyme-catalyzed reaction has been determined at a number of substrate concentrations. Data are given below. [S](mu*M) 5 10 20 50 100 200 500 vo (mu*Mmin-1) 21 62 92 126 185 210 217 a) Estimate Vmax and Km from a direct graph of vo vs [S] (Michaelis-Menton plot). b) Use a Lineweaver-Burk plot to analyze the same data. What are the values of Vmax and Km? c) If the total enzyme concentration is 100 pM, what is kcat? d) Calculate kcat/Km for this enzyme. Is the enzyme an efficient enzyme?

Solutions

Expert Solution

2) (a) Shwon below is the Michaelis-Menton plot for the given data point.

plot, [S] on x-axid and Vo on y-axis

Vmax = 217 mu.M/min

Km = 35 mu.M

(b) Shown below is the Lineraweaver-Burke plot

Plot 1/[S] on x-axis and 1/Vo on y-axis

y-intercept = 1/Vmax = 0.0364

Vmax = 27.47 mu.M/min

x-intercept = -1/Km = -0.0056

Km = 178.57 mu.M

Kcat = Vmax/[E] = 27.47/1 x 10^-4 = 274,700 min-1

(d) For this enzyme Kcat/Km = 274,700/178.57 = 1538.33 1/mu.M.min

The enzyme is an efficient enzyme.

Plots given below

[S](mu.M)	Vo(muM/m)	1/[S]	1/Vo
5	21	0.2	0.04762
10	62	0.1	0.01623
20	92	0.05	0.01087
50	126	0.02	0.00794
100	185	0.01	0.005405
200	210	0.005	0.004762
500	217	0.002	0.004608

queen_honey_blossom answered 1 year ago

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