Chemistry Reference
In-Depth Information
R
O
S
O
H
N
-
+
+
Carbonic
anhydrase
His
His
Zn
His
Figure 7.11
Schematic of the carbonic anhydrase active site showing the Zn(II) cation
coordinated to a benzenesulfonamide (ArSO
2
NH
2
) inhibitor molecule.
hydrazide
hydrazide
aromatic
sulfonamide
O
R
O
O
A
: R = H
B
: R = CH
3
C
: R =
i
Pr
D
: R =
i
Bu
E
: R = Ph
NH
2
NH
2
aldehyde
N
H
H
N
H
COOH
H
2
N
H
S
O
O
O
1
2
A
-
E
Figure 7.12
Fragments equipped with a hydrazide (
1
and
2
) or aldehyde (
A
-
E
) functional
groups for DCC utilizing hydrazone exchange and targeting carbonic anhydrase.
hydrazone exchange partners of
1
and
2
, were selected to introduce an array of 'tails' on to
1
to permit exploration of periphery recognition interactions with CA.
By monitoring a suite of control experiments using mass spectrometry, this study first
confirmed that hydrazone exchange was dynamic in the aqueous buffer used in the sub-
sequent
in situ
DCC mass spectrometry screening methodology. Then the
in situ
DCL of
acyl hydrazones (
1A
-
E
,
2A
-
E
) was generated in the presence of CA II. The fragments
and target were combined and incubated as follows: CA II (30 M),
1
(15 M),
2
(15 M)
and
A-E
(6 M each), in 10 mM NH
4
OAc (pH 7.2) with 1% DMSO to effect solubility, at
37
o
C for 40 h (Scheme 7.3). The final DCL volume was 50 or 100 L. The total access-
ible hydrazone concentration was equivalent to the concentration of CA II (30 M), while
individual hydrazone products could be formed to a maximum concentration of 6 Mor
20 mol% relative to CA II.
R
R
O
O
O
N
H
COOH
O
N
H
COOH
N
N
CA II
N
H
H
+
+ [CA II -
1A...1E
]
1
+
2
+
A-E
H
2
N
H
H
S
O
1A
-
1E
2A
-
2E
O
Scheme 7.3
Dynamic combinatorial library utilizing hydrazone exchange and targeting
carbonic anhydrase.
