metabolism of bioactive endogenous and …brandt/chem430/xenobiotic and...metabolism of bioactive...
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Metabolism of Bioactive Endogenous and Exogenous Compounds Oxidation Dehydrogenases Oxidases Cytochrome P450 enzymes Reduction Dehydrogenases Reductases Conjugation Sulfotransferases
3´-Phosphoadenosine5´-phosphosulfate
(PAPS)
3´,5´-adenosinebisphosphate
sulfotransferaseR OH R O S
O
O
OO S
O
OO
OHO
CH2O
N
N N
N
NH2
P
O
O
O
PO O
O
3´-Phosphoadenosine5´-phosphosulfate
(PAPS)
Glucuronases
O
N
HN
O
O
P
O
OO
OHOH
CH2OP
O
O
O O H
OH
OH
O
CH2HO
P
O
O
O O
α-Glucose-1-phosphate
P
O
O
O
Uridine Triphosphate(UTP)
+H
UDP-GlucosePyrophosphorylase N
HN
O
O
O
OHOH
CH2OP
O
O
O H
OH
OH
O
CH2HO
P
O
O
O O
UDP-Glucose
+H
O P
O
O
OHP
O
O
O
UDP-Glucosedehydrogenase
2 NAD+
H2O
2 NADH
N
HN
O
O
O
OHOH
CH2OP
O
O
O H
OH
OH
O
CO
P
O
O
O O
UDP-Glucuronic acid
H
O
UDP-glucuronosyltransferase
R OH
UDPUDP-Glucuronic acid
O H
OH
OH
O
CO
OH
O
R
Steroid Biosynthetic Pathways
HO Cholesterol
1
2
34
56
7
8
9
10
11
12
13
14 15
O
HO Pregnenolone
1617
18
19
20
2122
23
24
25
26
27
O
O
O
O
O
O
O
O
OH
OH
OH
HO
HO
O
O
O
O
O
O
O
OH
OH
HO
O
HO
OH
OH
OH
OH
O
HO
O
O
HO
O
O
OH
O
OH
HO
OH
O
O
S
O
O
O
P450scc
P45011β
3β-Hydroxysteroid Dehydrogenase/∆5-∆4-isomerase
P45
0 17 α
P45
0 17 α
P45021
P45018
P45018
P45
0 aro
m
17β-Hydroxysteroid Dehydrogenase
5α-Reductase
17α-Hydroxy-Pregnenolone
17α-Hydroxy-ProgesteroneProgesterone
Deoxycorticosterone
Corticosterone
Aldosterone
Dehydroepiandrosterone(DHEA)
DHEA-Sulfate
Deoxycortisol
Cortisol
Androstenedione
Testosterone
Dihydrotestosterone(DHT)
Estradiol
Estrone
Sulfotransferase
*
*
*
*
* – Denotes mitochondrial enzyme
P450scc (cholesterol side-chain cleavage enzyme)*
P45017α (17α-hydroxylase/lyase)
P45021 (21-hydroxylase)
P45011β (11β-hydroxylase)*
P45018 (18-hydroxylase)*
P450arom (aromatase)
Steroid Nomenclature
Steroid derivatives
Cholestane (C27) Pregnane (C21) Androstane (C19) Estrane (C18)
HO Cholesterol (cholest-5-ene-3β-ol)
1
2
34
56
7
8
9
10
11
12
13
14 15
1617
18
19
20
2122
23
24
25
26
27
HO OH
OH
O
O
Cholic acid HO OH
OH
NH
O
Taurocholic acid
S
O
O
O
HO
OH
O
O
Deoxycholic acid
Steroid Metabolism
NAD(P) NAD(P)H
11β-hydroxysteroiddehydrogenase
HO OH
O
OH
OCortisol
OH
O
OH
OCortisone
O
HO OH
O
OH
O
5α-reductase
3a-hydroxysteroiddehydrogenase
NADPH
NADP
H
5α-dihydrocortisol
HO OH
O
OH
HOH
Tetrahydrocortisol
5β-reductase
HO OH
O
OH
OH
3α-hydroxysteroiddehydrogenase
NADPH
NADP
HO OH
O
OH
HOH
3a-Tetrahydrocortisol
NADPH
NADP
20α-hydroxysteroiddehydrogenase
HO OH
OH
OH
HOH Cortol
O
O
OH
HO
O
Aldosterone
O
O
OH
O
HO
Aldosterone
Catecholamine Synthesis
Adrenal Medulla
OH
H3N
OO
Tyrosine
Tyrosinehydroxylase
[tetrahydrobiopterin]
NADPH NADP
OH
H3N
OO
OH
DOPA
CO2
DOPA decarboxylase
[PLP]
OH
H3N
OH
Dopamine
Dopamineβ-hydroxylase
Ascorbicacid
Dehydro-ascorbicacid
OH
H3N
OH
OH
Norepinephrine
S-adenosyl methionine
O
OHOH
CH2
N
N N
N
NH2
SO
O
NH3
CH3
S-adenosyl methionine
OH
H2N
OH
OH
Epinephrine
PhenylethanolamineN-methyltransferase
(PNMT)
CH3
S-adenosylhomocysteine
TyrosineTyrosine
hydroxylase[tetrahydrobiopterin]
NADPH NADP
DOPA
CO2
DOPA decarboxylase
[PLP]
Dopamine
Norepinephrine
S-adenosylmethionine
Epinephrine
PhenylethanolamineN-methyltransferase
(PNMT)
S-adenosylhomocysteine
Dopamine
Dopamineβ-hydroxylase
Ascorbicacid
Dehydro-ascorbicacid
Norepinephrine
Epinephrine
Cytoplasm
Secretory
Vesicle
Normetanephrine
Metanephrine
Catecholamine Breakdown
Catecholamine Breakdown
OH
H3N
OH
OH
Norepinephrine
Monamine Oxidase A[flavin]
O2 NH3
H2O2 OH
O
OH
OH
3,4-dihydroxy-phenylglycoaldehyde
H
Aldehydereductase
NADPH NADP
OH
OH
OH
3,4-dihydroxy-phenylglycol
HO
Nerve termini
OH
H3N
OH
Dopamine
Monamine Oxidase B[flavin]
OH
OH
H
O
O2 NH3
H2O2
3,4-dihydroxyphenylacetaldehyde
Aldehydereductase
NADPH NADP
OH
OH
3,4-dihydroxy-phenylethanol
HO
OH
H3N
OH
OH
Norepinephrine
S-adenosylmethionine
S-adenosylhomocysteine
Catechol-O-MethylTransferase
OH
H2N
OH
OH
Epinephrine
CH3
S-adenosylmethionine
S-adenosylhomocysteine
Catechol-O-MethylTransferase
OH
H3N
O
OH
Normetanephrine
CH3
OH
H2N
O
OH
Metanephrine
CH3
CH3
Peripheral tissues
MonamineOxidaseA
[flavin]
OH
O
O
OH
3-methoxy-4-hydroxy-phenylglycoaldehyde
H
CH3
Aldehydereductase
NADPH
NADP
OH
O
OH
3-methoxy-4-hydroxy-phenylglycol
CH3
HO
O2
O2
NH2
H2O2H3C
NH3
H2O2
OH
O
O
OH
3-methoxy-4-hydroxy-mandelic acid
(Vanillylmandelic acid)(VMA)
OH
CH3
OH
O
OH
3-methoxy-4-hydroxy-phenylglycol
CH3
HO
NAD NADH
Alcoholdehydrogenase
OH
O
O
OH
3-methoxy-4-hydroxy-phenylglycoaldehyde
H
CH3
OH
O
3-methoxy-4-hydroxy-phenylethanol
HO
NAD NADH
Alcoholdehydrogenase
CH3
OH
O
O
3-methoxy-4-hydroxy-phenylacetaldehyde
H
CH3
NADH
Aldehydedehydrogenase
NADH
Aldehydedehydrogenase
Liver
NAD+ H2O
NAD+ H2O
OH
O
O
3-methoxy-4-hydroxy-phenylacetic acid
(Homovanillic acid)
OH
CH3
Consequences
O
O
N
CH3
CH3
O
N
CH3
O CH3
Meperidine(Demerol)
1-Methyl-4-propionoxypiperidine
(MPPP)
H+
HeatN
CH3
N-Methyl-4-phenyl1,2,3,6 tetrahydropyridine
(MPTP)
MonoamineoxidaseB
N
CH3
MPDP+
N
CH3
1-Methyl-4-phenylpyridinium
(MPP )+
N
HH3C
CH3
Selegiline
HO
HONHH3C
OH
O
CarbidopaNH2
HO
HO
NO2
C
N
O
CH3
CH3
NEntacapone
Acetaminophen Metabolism
UDP-Glucuronic acid
O
OH
OH
OH
C O
O N
NH
O
O
P
O
OO
OHHO
CH2OP
O
O
O
O
O
OH
OH
OH
C O
O
O
NHCH3
O
NHCH3
O
HO
Acetaminophen
N
NH
O
O
P
O
OO
OHHO
CH2OP
O
O
OO
O P
O
O
O
O S
O
OO
OH
CH2O
N
N N
N
NH2
P
O
O
O
3´-phosphoadenosine5´-phosphosulfate (PAPS)
glucuronyltransferase
sulfotransferase
NHCH3
O
HO
Acetaminophen
O S
O
O
O NHCH3
O
O P
O
O
O
O
OH
CH2O
N
N N
N
NH2
P
O
O
O
UDP
adenosine3´,5´-bisphosphate
NHCH3
O
HO
Acetaminophencytochrome P450
(CYP2E1,CYP1A2,CYP2D6)
NH3C
O
OHHO
NH3C
O
O
Acetimidoquinone
SpontaneousH2O
HN
O
HN
O
O
OH3N
O O
HS
γ-Glu
Cys Gly
Glutathione(reduced form)HN
O
HN
O
O
OH3N
O O
S
HNH3C
O
OH
Cys-Protein
S
HNH3C
O
OHProtein-Cys-SH
Spontaneous
Spontaneous
Cytochrome P450 Enzymes in Humans (from http://drnelson.uthsc.edu/human.P450.table.html) Family Known
genes Comments
CYP1 CYP1A1 CYP1A2 CYP1B1
Xenobiotic and endogenous bioactive catabolism, carcinogen activation
CYP2 CYP2A6 CYP2A7 CYP2A13 CYP2B6 CYP2C8 CYP2C9 CYP2C18 CYP2C19 CYP2D6 CYP2D7 CYP2E1 CYP2F1 CYP2J2 CYP2R1 CYP2S1 CYP2U1 CYP2W1
Xenobiotic and endogenous bioactive catabolism
CYP3 CYP3A4 CYP3A5 CYP3A7 CYP3A43
Xenobiotic and endogenous bioactive catabolism
CYP4 CYP4A11 CYP4A22 CYP4B1 CYP4F2 CYP4F3 CYP4F8 CYP4F11 CYP4F12 CYP4F22 CYP4V2 CYP4X1 CYP4Z1
Fatty acid hydroxylation
CYP5 CYP5A1 Platelet thromboxane A synthase 1 CYP7 CYP7A1
CYP7B1 7A1 is liver enzyme: 7α-hydroxylase; catalyzes the main regulated step in bile acid synthesis 7B1 is non-liver, and may be involved in steroid metabolism
CYP8 CYP8A1 CYP8B1
8A1 is prostaglandin I2 (prostacyclin) synthase 8B1 intronless; 12α-hydroxylase in bile acid synthesis pathway
CYP11 CYP11A1 CYP11B1 CYP11B2
Mitochondrial steroid hormone biosynthesis enzymes 11A1 is cholesterol side-chain cleavage enzyme, the main regulated step in steroid hormone biosynthesis. 11B1 is 11β-hydroxylase 11B2 is 18-hydroxylase
CYP17 CYP17A1 17α-hydroxylase/17-20 lyase in steroid hormone biosynthesis pathway
CYP19 CYP19A1 Aromatase CYP20 CYP20A1 Present in many species, but deviates from P450 consensus
sequence; function unknown CYP21 CYP21A2 21-hydroxylase (pseudogene nearby causes high rate of
inborn errors) CYP24 CYP24A1 24-hydroxylase for 1α-25-dihydroxyvitamin D in breakdown
pathway CYP26 CYP26A1
CYP26B1 CYP26C1
Retinoid 4-hydroxylase and 18 hydroxylase
CYP27 CYP27A1 CYP27B1 CYP27C1
27A1 hydroxylase in bile acid synthesis pathway 27B1 1α-hydroxylase of 25-hydroxyvitamin D; catalyzes regulated activation step for vitamin D 27C1 function unknown
CYP39 CYP39A1 7α-hydroxylase in bile acid synthesis pathway CYP46 CYP46A1 Cholesterol 24S-hydroxylase in brain CYP51 CYP51A1 Lanosterol 14-demethylase in cholesterol synthesis pathway Inducers and inhibitors
HN
NH
O
O OPhenobarbital
O OO
O
Bergamottin
O OO
O
Dihydroxybergamottin
OH
HO
Tamoxifen Metabolism
Additional demethylation Isomerization Sulfotransferases N- and O-glucuronide formation
ONCH3
CH3
Tamoxifen
Cytochrome P4503A4
Cytochrome P4502D6
others
ONH
CH3
N-desmethyltamoxifen
Cytochrome P4503A4
Cytochrome P4502D6
othersO
NCH3
CH3
trans-4-hydroxytamoxifen
HO
Cytochrome P4502D6
ONH
CH3
(Z)-endoxifen
HO
Cytochrome P4503A4
Cytochrome P4502D6
others
Estrogens and Related Compounds
HO17β-Estradiol
HO
OH
Diethylstilbestrol(DES)
OH
HOEquilin
O
HOEthinylestradiol
OH
O
OOH
HO
OH
Genistein
O
O
OH
O
HOCoumestrol
ON
Tamoxifen
SOH
O
ON
HO
Raloxifene
Members of the Nuclear Receptor Superfamily
Receptor Ligand Length (residues) Chromosome
Thyroid hormone-α Thyroid hormone-β (triiodothyronine)
490 456
17 3
Vitamin D (1α,25-dihydroxyvitamin D)
427 12
Retinoic acid-α Retinoic acid-β Retinoic acid-γ (all trans retinoic acid)
462 448 454
17 3
12
Retinoid-X-α Retinoid-X-β Retinoid-X-γ (9-cis-retinoic acid)
462 533 454
9 6 1
Estrogen-α Estrogen-β (estradiol)
595 530
6 14
Glucocorticoid (GR type II) (cortisol)
777 5
Mineralocorticoid (GR type I) (aldosterone)
984 4
Androgen (testosterone)
919 X
Progesterone (progesterone)
769 (A) 933 (B) 11
O
NH3
OO
I
I
I
HO
HO
OH
OH
O
O
OO
OH
HO
O
OH
O
OHHO
O
O
OH
HO
O
O
OH
O
O
Domain Structure of the Nuclear Receptors
Variable (A/B) DBD (C) D LBD (E) F
Variable Domain DNA-binding Domain (DBD)
hinge Ligand-Binding Domain (HBD)
None ?
Dimerization Dimerization
Transactivation Transactivation Transactivation
hsp90 binding
hsp90 binding
Nuclear localization
Nuclear localization
Highly Conserved Somewhat conserved
LBDVariable DBD
Features of Selected Receptor Proteins
DNA Binding Domain
Ligand- Binding Domain
Receptor Size of
variable domain
Size (amino acids)
% Identity
Size (amino acids)
% Identity
Glucocorticoid (GR Type II)
421 66 100 250 100
Mineralocorticoid (GR Type I)
603 66 94 251 57
Progesterone 567 66 90 255 55 Androgen 559 66 91 243 52
Estrogen-α 180 66 53 250 30 Thyroid hormone-β 102 67 47 225 17
Retinoic acid-α 88 66 45 265 15 Vitamin D 24 66 42 236 <15%
(from pdb ID 3DZY)
L
LL
LL
L
RNA
pdb ID 3ERD (ER LBD Dimer bound to DES and LXXLL peptide)
Overlay of pdb ID 1QKU (estradiol bound ER LBD) and 3ERT (4-hydroxytamoxifen bound ER LBD)