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726 Chapter 21
Copyright © 2017 Pearson Education, Inc.
68.
a.
NH
3
NH
2
C N
RCHC N
NH
2
HCl
H
2
O,
RCHCOOH
NH
3
+
intermediate
trace
acid
I
intermediate II
−
+
H R
H R
C
O
C
b.
CH
3
CHCH
2
CH
3
CH
3
CHCH
2
CH
CH
3
NH
3
+
leucine
3-methylbutanal
H
OH
C
O
C
O
c.
isoleucine
CH CH
O
−
CH
3
CH
2
NH
3
+
C
O
CH
3
2-methylbutanal
CH H
CH
3
CH
2
C
O
CH
3
69.
Ser-Glu-Leu-Trp-Lys-Ser-Val-Glu-His-Gly-Ala-Met
From the experiment with carboxypeptidase A, we know that the C-terminal amino acid is Met.
“Fragment 12” tells us the amino acid adjacent to Met is Ala.
“Fragment 5” tells us the next amino acid is Gly.
“Fragment 2” tells us the next amino acid is His.
“Fragment 7” tells us the next amino acid is Glu.
“Fragment 10” tells us the next amino acid is Val.
“Fragment 3” tells us the next amino acid is Ser.
“Fragment 9” tells us the next amino acid is Lys.
“Fragment 1” tells us the next amino acid is Trp.
“Fragment 8” tells us the next amino acid is Leu.
“Fragment 11” tells us the next amino acid is Glu.
“Fragment 4” tells us the next (first) amino acid is Ser.
70.
a.
x
y
=
the number of amino acids
y
=
the number of spots in the peptide for each amino acid
20
8
=
25,600,000,000
b.
20
100
=
1.3
*
10
130