Calculate Km and Vmax from the following data.docx

Biochemistry

Lec. of

Biochemistry Dr. Mahmoud H. Hadwan

Q1/ Calculate Km and Vmax from the following data: [S] (µM) V0 0.1 0.2 0.4 0.8 1.6

0.34 0.53 0.74 0.91 1.04

Q2/ Determine the type of inhibition of an enzymatic reaction form the follwoing data collected in the presecnce and absence of the inhibitor

[S] 1 2 4 8 12

[V0] 1.3 2.0 2.8 3.6 4.0

V0 with I present 0.8 1.2 1.7 2.2 2.4

Q3/ For an enzyme (5 μM) , the following initial velocities have been reported depending on the substrate concentration:

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(a) Draw a Michaelis-Menten plot for this enzyme. (b) Draw a Lineweaver-Burke plot for this enzyme. (c) Determine KM and Vmax for this enzyme (d) Indicate in both graphs (a & b) where Vma and KM can be recognized.

Q4/ Given the reaction of an enzyme that follows Michaelis-Menten kinetics: k1

kp

E + S  ES  E + P k-1

If Km = 30 mM and Vmax = 60 uM min-1

a)

What is the initial reaction velocity at a substrate concentration of 0.1 mM?

b)

What is the initial reaction velocity at a substrate concentration of 30 mM?

c)

What is the initial reaction velocity at a substrate concentration of 1000 mM?

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Q5/ An experiment was carried out using a food enzyme and gave the following results.

1.

plot Lineweaver-Burke for the data is reproduced below.

2. Comment on the resulting graphs 3. Estimate values of Vmax and Km for this data.

Q6/ The following data were obtained from an enzyme kinetics experiment. Graph the data using a Lineweaver-Burk plot and determine, by inspection of the graph, the values for Km and Vmax. [S] (µM) V (nmol/min) _______

___________

1.20 1.26 1.33 1.1

1.43 1.67 2.08 3.33

Q7/ Use the Michaelis-Menton Equation to calculate the missing values of [S] given below if Vmax = 5 mmol/min. Plot [S] versus V (NOT the reciprocals!). Draw line parallel to the x-axis at Vmax and extend your plotted line to show its approach to Vmax.

[S] (mM)

V (mmol/min)

_______

___________

10 ?

1.2 1.7

?

2.1

?

2.2

?

2.5

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Biochemistry

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Q8/ The effect of an inhibitor on an enzyme was tested and the experiment gave the results below. Plot the data and determine, by inspection of the graph, what type of inhibition is involved. [S] µM

______

V (µmol/min)V (µmol/min)V (µmol/min) with 0.0 nM with 25 nM

with 50 nM

Inhibitor

Inhibitor

Inhibitor

___________

___________

___________

0.4

0.22

0.21

0.20

0.67

0.29

0.26

0.24

1.00

0.32

0.30

0.28

0.36

0.32

2.0

0.40

Q9/ The following data were obtained from an enzyme kinetics experiment. Graph the data using a Lineweaver-Burk plot and determine, by inspection of the graph, the values for Km and Vmax.

[S] (µM)

V (nmol/min) 4

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_______

___________

1.21 1.27 1.34

1.43 1.67 2.08 2.1 3.33

Q10/ Use the Michaelis-Menton Equation to calculate the missing values of [S] given below if Vmax = 5 mmol/min. Plot [S] versus V (NOT the reciprocals!). Draw line parallel to the x-axis at V max and extend your plotted line to show its approach to V max. [S] (mM)

V (mmol/min)

_______

___________

11 [S]1

1.2 1.7

[S]2

2.1

[S]3

2.2

[S]4

2.5

Q11/ The effect of an inhibitor on an enzyme was tested and the experiment gave the results below. Plot the data and determine, by inspection of the graph, what type of inhibition is involved. [S] µM

______

V (µmol/min)V (µmol/min)V (µmol/min) with 0.0 nM with 25 nM

with 50 nM

Inhibitor

Inhibitor

Inhibitor

___________

___________

___________

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Biochemistry

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0.4

0.22

0.21

0.20

0.67

0.29

0.26

0.24

1.00

0.32

0.30

0.28

2.00

0.40

0.36

0.32

Additional

Plot of Michaelis-Menton Kinetics

Plot Lineweaver-Burke of COMPETITIVELY inhibited M-M reaction Plot Lineweaver-Burke of Uncompetitive Inhibition

Plot Lineweaver-Burke with Mixed Inhibition

6

Calculate Km and Vmax from the following data.docx

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