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Faculty of Science, IUG
Dept. of Chemistry and Biochemistry
Mid-Term Exam.
Enzymes kinetics(Bioc4307)
Date: 22/11/2006 Name:----------------, NO.-----------
Answer the following:
I-Account for the following (10 pts).
A)Pepsin is not used in AA sequencing.
B)Some enzymes are found in multi-enzyme
complex.
C)Lactose synthase does not act during
pregnancy.
D)Induced fit mechanism is more acceptable than
lock and key mechanism.
E)Catalytic power of enzymes depend on the
environment in which they are present.
II- Starting from M.M. equation, prove that [p] =
Vmax. t showing plots of V, [S] and [P] vs. t. (6pts).
III- Rearrange the M.M. equation to give Vo as a
function of Vo/[s] and plot it (3 pts).
A) What is the slope, Y-intercept, and Xintercept (3 pts).
B) Sketch the plot in presence of CI and
NCI(4pts).
IV- Given the following data:
[S]µM
Vo µM/min.(-I)
Vo µM/min.(+I)
3
10.4
4.1
5
14.5
6.1
10
22.5
11.3
30
33.8
22.6
90
40.5
33.8
A) Draw L.B. plot (4pts).
B) Determine Vmax (± I) , Km (± I),type of
inhibition, and Ki if [I] is 2mM (8pts).
c)At [S] = 10 µM, and [I] = 2mM, What fraction of
the enzyme molecules have a bound substrate and a
bound inhibitor? (2pts)
Faculty of Science, IUG
Dept. of Chemistry and Biochemistry
Midterm Exam.
Chemistry of proteins and lipids(Bioc4308)
Midterm Exam
Date:2/12 /2005 Name----------- & NO.----------Answer the following
I- Sketch the titration curve, calculate pI and
determine the regions of the buffer capacity of ASP. The
pK values of its Alfa COOH, Alfa amino , and Beta COOH
groups are 2.1, 9.2, and 3.9 respectively. (6pts).
II-Compare and contrast
1-Fatty acid oxidation and synthesis with respect of site
of the process, acyl carrier, reductant and oxidant, the
net equation, sequential units added, organization of the
enzyme systems (6pts).
2- Lowery method and Biuret methods with respect of
composition, reaction with a protein, sensitivity, the
wave length of absorbance (4pts).
III-Discuss by showing structure of the following
biochemical processes(15pts).
1-Keto-genesis.
2-Synthesis of TAG starting from glycerol.
3-Transfer of acetylCoA from mitochondria to cytoplasm by
malate-oxaloacetate shuttle.
Faculty of Science, IUG
Dept. of Chemistry and Biochemistry
Incomplete Exam.
Chemistry of proteins and lipids(Bioc4308)
Date: March/2006 Name----------- & NO.----------Answer the following
I)-Write structural formulas of the following biochemical
processes.
1-Ketolgenesis.
2-Formation of Cyst. From Met.
3-Formation of Gly from Glyceraldehyde 3- p.
4- Formation of TAG from glycerol in a small intestinal
cell.
II)-Write the following biochemical processes (without
Structural formulas).
1-Fate of heme in the body.
2-Formation of linoleic acid (18:Dalta9,12) from oliec
acid(18:dalta9)in the body.
III)- Sketch the approximate titration curve for:
1- Glutamic acid.
2- Lysine.
Faculty of Science, IUG
Dept. of Chemistry and Biochemistry
Final Exam.
Enzymes kinetics(Bioc4307)
Date: 11/1/2006
Name:----------------, NO.-----------
Answer the following:
I- Starting from M.M. equation, derive Ln [S]0/[S] = /K t and show plots of V, [S]
and [P] vs. t. (10pts).
II- Rearrange the M.M. equation to give [s]o/Vo as a function of [s]o and plot it (4 pts).
1-What is the slope, Y-intercept, and X-intercept
(3 pts).
2-Sketch the plot in presence of CI, NCI, and UNCI
(3 pts).
III- Given the following data:
[S]µM
Vo µM/min.(-I)
Vo µM/min.(+I)
3
10.4
2.1
5
14.5
2.9
10
22.5
4.5
30
33.8
6.8
90
40.5
8.1
1- Draw L.B. plot (4pts).
2- Determine Vmax (± I) , Km (± I),type of inhibition, and Ki if [I] is 100 µM (8pts).
3- If [s] = 30 µM, what fraction of the enzyme molecules have a bound substrate (±
I)?(4 pts)
IV- If a pure enzyme has a specific activity of 200 U/mg enzyme(6 pts).
a)Calculate the Kcat if M.W. of the enzyme is 200,000 Dalton (explain the answer).
b)Calculate the time required for one catalytic cycle(explain the answer).
V-(a) What concentration of competitive inhibitor is required to yield 25% activation
at a substrate concentration of 1.5x10-3 M if Km = 2.9x10-4 M and Ki = 2x10-5 M?(5
pts).
(b) Calculate concentration of the substrate that must be increased to reestablish the
velocity at the original uninhibited value?(2pts).
VI- For 120 µM/min units of a pure enzyme preparation (10 mg/ml,360000 Dalton).
Calculate: kp,1/Kp and S.A(7 pts).
VII)Complete the following enzyme purification scheme (12 pts).
Total
Volume
Conc
Enzyme
Step
units
S.A % Yield
(ml)
(mg/ml)
(U/ml)
Crude cell free
extract
Ammonium sulfate
Heat denaturation
1000
10
40
250
100
20
40
100
200
PF