Chemistry Reference
In-Depth Information
TABLE 4.11. Rate Constants for Reactions of Amino Acids, Peptides, and Proteins
with
•
OH Radical
Amino Acid
pH
k
(/M/s)
Peptide
pH
k
(/M/s)
gly
5.9
1.7 × 10
7
N
-Ac-gly
6.6-8.7
4.0 × 10
8
Asn
6.6
4.9 × 10
7
gly-gly
5.5-7
2.4 × 10
8
Asp
6.9
7.5 × 10
7
cyclo(gly-gly)
5.0
1.2 × 10
9
Ala
5.8
7.7 × 10
7
8.6
7.8 × 10
8
N
-Ac-gly-gly
2.3 × 10
8
7.3 × 10
8
glu
6.5
(gly)
3
5.4
Ser
∼6.0
3.2 × 10
8
(gly)
4
5.5
4.5 × 10
8
Lys
6.6
3.5 × 10
8
N
-Ac-Ala
6.6-9.2
4.7 × 10
8
Thr
6.6
5.1 × 10
8
cyclo(Ala-Ala)
5.0
1.8 × 10
9
gln
6.0
5.4 × 10
8
N
-Ac-(Ala)
3
9.0
3.0 × 10
9
Pro
6.8
6.5 × 10
8
Val
6.9
8.5 × 10
8
1.7 × 10
9
Leu
∼6.0
Ile
6.6
1.8 × 10
9
cystine
6.5
2.1 × 10
9
Arg
6.5-7.5
3.5 × 10
9
His
7.5
4.8 × 10
9
Phe
7-8
6.9 × 10
9
Met
6-7
8.5 × 10
9
Tyr
7.0
1.3 × 10
10
1.3 × 10
10
Trp
6.5-8.5
cys
7.0
3.5 × 10
10
Lysozyme
5.6-7
≈5 × 10
10
HSA
7.0
7.8 × 10
10
O
R
O
R
O
R
O
2
•
HO
•
N
H
2
O
N
O
2
N
H
H
•
H
R1
R2
R1
R2
R1
R2
O
O
O
•
OOH
O
O
•
O R
O
2
H
O
R
R
N
N
N
H
H
R1
R2
R1
R2
R1
N
R2
O
O
O
H
2
O
R
=
Side chain of amino acid
R1, R2
=
N- and C-terminal
parts of protein molecule
R
N
O
O
O
N
•
R2
+
+
H
NH
2
R2
R1
O
R1
R
O
O
O
2
CO
2
•
OOH
O C N R2
NH
3
+
R2
Figure 4.20.
H-abstraction at the α-carbon site of the protein (adapted from xu and
chance [261] with the permission of the American chemical Society).
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