720 / 912
712 Chapter 21
Copyright © 2017 Pearson Education, Inc.
b.
+
H
3
NCH
C
NHCH NH
C
O
CH
2
CH
N
H
CH
2
S
S
O
C
CH
2
CH
2
CH
O
O
−
C
O
OH
30.
O
N
O
O NH
3
_
+
OCH
3
O
H
S
S
31.
a.
glutamate, cysteine, and glycine
b.
In forming the amide bond between glutamate and cysteine, the amino group of cysteine reacts with
the
g
-carboxyl group of glutamate rather than with its
a
-carboxyl group.
O
O
O
O
NH
3
_
_
_
glutamate
+
-carboxyl
group
-carboxyl
group
N
O
O
O
NH
3
O
N
SH
O
O
_
glutathione
amide bond
+
-carboxyl
group
-carboxyl
group
H
H