Cytochrome P450
105
Tab. 1
Classifcation oF P450s
according to substrate metabolism.
Endogenous substrate metabolism
Examples
Steroid hormone biosynthesis
Vitamin D
3
metabolism
Cholesterol biosynthesis
Bile acid biosynthesis
Reactions
Hydroxylations
C
Cbondlys
is
Exogenous substrate metabolism
Examples
Environmental pollutant metabolism
Drug metabolism
Insect metabolism oF plant toxins
Reactions
Hydroxylations
N
-Dealkylations
O
-Dealkylations
Alcohol oxidation
Alkane oxygenations
SOH
P450-SH
(Fe
3
+
)
P450-SH
(Fe
2
+
)
P450-SH
(FeOOH)
P450-SH
(Fe
2
+
O
2
)
P450-SH
(FeO
3
+
)
P450-SOH
(Fe
3
+
)
H
2
O
O
2
+
SH
+
e
+
e
+
H
+
+
H
+
P450
(Fe
3
+
)
Fig. 1
Generalized catalytic cycle For cytochromes P450.
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