SOME OTHER IMPORTANT NUCLEOSIDES AND NUCLEOTIDES: ATP, SAM, COENZYME A, NAD, FAD
561
O
HO
OH
N
CONH 2
N
N
N
NH 2
RO
OH
O
N
CH 2
CH 2
R = H, NAD
+
R = P, NADP
+
adenine
ribose
ribose
nicotinamide
≡
ribose
nicotinamide
ribose
adenine
O
CH 2
HO
O
O CH 2
HO
OR
P
O
OH
O
P
O
OH
O
OH
N
CONH 2
nicotinamide
N
N
N
NH 2
N
adenine
≡
adenine
nicotinamide
O
P
O
O
P
O
O
OH OH
P
P
P
P
P
P
N
N
N
NH 2
HO
OH
O
N
N
N
N
NH
H 3 C
H 3 C
O
O
OH OH
OH
CH 2
FMN
≡
O
O CH 2
HO
OR
P
O
OH
O
P
O
OH
O
N
N
N
NH 2
N
adenine
N
N
N
NH
H 3 C
H 3 C
O
O
OH OH
OH
adenine
flavin
flavin
adenine
ribose
ribitol
flavin
≡
ribitol
flavin
ribose
adenine
O
P
O
O
P
O
O
OH OH
FAD
P
P
P
P
Box 14.3
Cyclic AMP
The nucleotide cyclic AMP (3
,5
-cyclic adenosine monophosphate, cAMP) is a cyclic phosphate ester of
particular biochemical significance. It is formed from the triester ATP by the action of the enzyme adenylate
cyclase, via nucleophilic attack of the ribose 3
-hydroxyl onto the nearest P=O group, displacing diphosphate as
leaving group. It is subsequently inactivated by hydrolysis to 5
-AMP through the action of a phosphodiesterase
enzyme.