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734 Chapter 21
Copyright © 2017 Pearson Education, Inc.
8.
Identify the spots.
chromatography
Asp
Ile
Lys
Phe
Ser
Tyr
+
−
electrophoresis
pH = 5
9.
Calculate the pI of the following amino acids:
a.
phenylalanine
1
p
K
a
s
=
2.16, 9.18
2
b.
arginine
1
p
K
a
s
=
2.17, 9.04, 12.48
2
10.
From the following information, determine the primary sequence of the decapeptide:
a.
Acid hydrolysis gives Ala, 2 Arg, Gly, His, Ile, Lys, Met, Phe, Ser.
b.
Reaction with Edman’s reagent liberates Ala.
c.
Reaction with carboxypeptidase A liberates Ile.
d.
Reaction with cyanogen bromide (cleaves on the C-side of Met)
1.
Gly, 2 Arg, Ala, Met, Ser
2.
Lys, Phe, Ile, His
e.
Reaction with trypsin (cleaves on the C-side of Arg and Lys)
1.
Arg, Gly
2.
Ile
3.
Phe, Lys, Met, His
4.
Arg, Ser, Ala
f.
Reaction with thermolysin (cleaves on the N-side of Leu, Ile, Phe, Trp, Tyr)
1.
Lys, Phe
2.
2 Arg, Ser, His, Gly, Ala, Met
3.
Ile
11.
Describe how acetaldehyde can be converted to alanine.
12.
Draw the mechanism for the conversion of a thiol to a disulfide in a basic solution of Br
2
.