Metal Cofactors
Porphyrin (without Fe) and Heme (with Fe)
R1
N
N
heme a
N
R1
N
CO2
N
N
N
CO2
-CH=CH2
heme c
-CH=CH2 -CH(CH3)Scys
R2 -CHOHC16H27 -CH=CH2 -CH(CH3)Scys
Fe
N
heme b
R3
-CHO
-CH3
-CH3
R2
R3
Corrin
Chlorin
Siroheme
1– charge, one less bond
partial delocalization
2– charge
1 double bond lost
2– charge
two double bonds lost
HO2C
N
N
N
N
CO2H
HO2C
CH3
N
N
N
N
N
CO2H
N
HO2C
Pheophytin (without Mg)
and Chlorophyll (with Mg)
CO2H
Fe
HO2C
N
N
R2
R3
R1
N
N
Mg
N
N
CH3
CO2H
CH3
R1
R2
R3
chl a
-CH3
-CH=CH2
-CH3
chl b
-CH3
-CH=CH2 -CHO
chl d
-CH3
-CHO
-CH3
chl f
-CHO
-CH=CH2
-CH3
H
O
3
O
O
CH3OC
O
Mo or W MPT (Mo or W molybdopterin)
O
HN
H2N
N
H
N
N
H
S
MLn
S
O
M = Mo, W
OPO3R–
R = H, PO2(OH)(nucleoside)
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Biological Electron and Energy Carriers
Electron Carriers: NAD+, flavins, pterins, quinones
NAD+ or NADP+ (nicotinamide adenine dinucleotide (phosphate))
NH2
CONH2
N
N
N
N
O
HO
NH2
N
R
OR = H, NAD+
= OP(OH)2, NADP+
HO
OH
N
N
N
O
CONH2
H+ 2e–
NADH
or NADPH
FAD (flavin adenine dinucleotide)
N
N
O O
OPOPO
HO OH
O
HO
OH
O O
OPOPOCH2(CHOH)3CH2
HO OH
H3C
N N
O
R
2H+ 2e– H3C
N
H3C
N
H
NH
N
H3C
FADH2
O
H
N
O
NH
O
FMN (flavin mononucleotide)
O
(HO)2POCH2(CHOH)3CH2
H3C
N
H3C
N
FMNH2
N
2H+ 2e–
O
NH
R
H3C
N
H
N
H3C
N
H
O
O
O
BH4 (tetrahydrobiopterin)
BH2
O
O
N
N
(CHOH)2CH3
H2N
N
R
R
R
R
+
–
H e
R
R
R
R
H e
O•
O
–
O
R
MeO
R
R
MeO
N
H
CH3
H
O
OH
n
Vit K1 (phylloquinone)
O
O
CH3
(CHOH)2CH3
O
R
PQ (plastoquinone)
MQ (menaquinone, Vit K2)
N
H
N
Q (ubiquinone, Coenzyme Q)
OH
+
HN
H2N
N
H
quinol
OH
–
2H 2e
NH
quinone
O
+
CH3
CH3
CH3
H
O
CH3
n
H
O
O
9
Energy Carrier: ATP
NH2
ATP (adenosine triphosphate)
N
N
N
O O O
N
HO
OPOPOPOH
O O O
H H H
O
+ H2O
– H2O
ADP
Pi
O O
OPOPOH
R
O O
H H
–
+ H2PO4
+ 30.5 kJ/mol
OH
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