Problemario Ing Enzimatica 1

IPN-UPIIG

Ingeniería Biotecnológica

Ingeniería Enzimática

Problem 1.-An assay was performed with the penicillinase enzyme. The amount of hydrolyzed penicillin per minute was measured as a function of the penicillin concentration (see table). Calculate the value of K M and Vmax. Data Penicillin μM 1 3 5 10 30 50

Solution Hydrolyzed (nmoles/min) 0.11 0.25 0.34 0.45 0.58 0.61

Problem 2.-The kinetics of an enzyme is measured as a function of the substrates concentration ([S]) in the presence of an inhibitor at a concentration of 2mM. Calculate K M and V max in the absence and presence of an inhibitor Mention what type of inhibition is involved What is the value of K I ? Data

Solution

[S], mM

Velocity (μmol/min) Sin I Con I

3 5 10 30 90

10.4 14.5 22.5 33.8 40.5

4.1 6.4 11.3 22.6 33.8

Problem 3.- The kinetics of an enzyme is measured as a function of the substrate concentration ([S]) with another type of inhibitor at a concentration conc entration of 100μ 100μM. Calculate K M and Vmax in the absence and presence of an inhibitor. Mention what type of inhibition is involved What is the value of K I ?

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Data


Solution

[S], mM

Velocity (μmol/min) Sin I Con I

3 5 10 30 90

10.4 14.5 22.5 33.8 40.5

2.1 2.9 4.5 6.8 8.1

Problem 4- A yeast disaccharide can hydrolyze sucrose and maltose, according to the table below. It is understood that sucrose and maltose are the substrate, and the glucose the released product expressed as the reaction rate. Investigate which are the reactions in each case and calculate the K M and Vmax for each substrate, and identify which is the natural substrate of the enzyme. Saccharose (mM) 5 10 20 50 100

Vo (μmol Glucose /10 min) 40 60 80 100 109

Maltose (mM) 5 10 20 50 100

Vo (μmol Glucose /10 min) 48 80 120 172 200

Problem 5.- An experiment was conducted where the rate of reaction of an enzyme with different inhibitor concentrations was measured, the results are below. a) Using the representation L-B determine the type o f inhibition b) Calculate the kinetic parameters K M , V max and K I for each concentration of inhibitor. Remember that the parameter K M and V max that varies more in percentage in relation to the kinetics without inhibitor would indicate which type of inhibition is involved. Data Vo, [µmol/min] [S] mM 0.05 0.1 0.15 0.2 0.25 0.3

[I]= 0.00 2.62 4.54 5.72 6.67 7.43 7.90

[I]= 1.393 1.77 3.00 3.84 4.77 5.00 5.42

[I]= 2.790 1.40 2.32 3.00 3.50 4.06 4.48

[I]= 4.180 1.29 2.10 2.66 3.11 3.55 3.74

0.4

9.04

6.07

4.80

4.17

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IPN-UPIIG Ingeniería Biotecnológica Ingeniería Enzimática Problem 6.- From a series of flasks with a constant concentration of enzyme the following initial velocities were taken, they were obtained as a function of the concentration of the substrate. a) Calculate the K M and V max kinetic parameters of the three forms (Lineweaver-Burk, Eadie-Hofstee, Dixon). b) Analyze which are the atypical data that cause a low correlation, which can be eliminated and explain your answer. Data

Solution

[S] mmol/L 1 2 3 5 7 10 15 20

[Velocidad reacción] mmol/L min 0.2 0.22 0.3 0.45 0.41 0.5 0.4 0.33

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-2

Problem 7.- An enzyme whose K M is 10 M in the presence of a 10 M substrate concentration, is capable of transforming 20% of the S into 10 min. Calculate the approximate percentage of S transformed in 20 min.

Problem 8.- The following table shows fractional saturation data for hemoglobin (S) and the partial oxygen pressure in plasma (pO2 ). Determine the value of the Hill coefficient and p0.5 for this enzyme. pO 2 , mmHg S

10

20

30

40

50

60

70

80

90

100

0.18

0.40

0.65

0.80

0.87

0.92

0.94

0.95

0.95 0.96

110

120

0.96

0.97

Problem 9.- Calculate the denaturing constant (k d ) and the reaction rate at 55 minutes of an enzyme having a thermal denaturation at 50 ° C following a first order kinetics; this enzyme has a reaction rate at the initial time of [r] 0 = 0.11 mmol / min Time (min) 10 20 30 40 50

[] mmol/min 0.0976 0.0867 0.0770 0.0680 0.0606 3

IPN-UPIIG 60 70 80 90



0.0538 0.0478 0.0424 0.0377

Problem 10.- The amyloglucosidase enzyme is immobilized on polyacrylamide gels. The activities of the immobilized enzyme and the soluble enzyme are compared at 80 ° C. The speed data is shown in the following table. Determine for both systems the values of k d as well as half-life. Time (min) 0 3 6 9 15 20 25 30 40

Soluble,

Immobilized,

[=]μmol/ mL*min

[=]μmol/ mL*min

0.86 0.79 0.70 0.65 0.58 0.469 0.41

0.45 0.44 0.43 0.43 0.41 0.40 0.39 0.38 0.37

Problem 11.- The following graphs show 3 straight lines associated with a kinetics without inhibitor (S), with inhibitor (I), and double concentration of inhibitor (2I). Explain for each set of lines what type of inhibition they present and which straight line corresponds to the one with the highest concentration of inhibitor. Justify your answers.

a b c __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ _____________________________________________________ 4

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a b c __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ ______________________________________________________

a b c __________________________________________________________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ ______________________________________________________

Bibliography. 1) Chang Raymond. 2009. “Fisicoquímica” Editorial McGraw Hill Interamericana. 3ra edición / Rústica / Castellano / Libro ISBN13:9789701066522 2) Doran M. P. “Principios de Ingeniería de los Bioprocesos”. Editorial Acribia S. A. ISBN: 84-200-0853-2 3) Illanes Andres. “Enzyme biocatalysis, principles and applications”. Editorial Springer Science. ISBN 978-1-4020-83600.ZMG49 4) Levenspiel Octave. 2009. “Ingeniería de las Reacciones Químicas”. Editorial Limusa Wiley. 3ra edición. 5) Fogler H. S.

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Problemario Ing Enzimatica 1

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