Record Information
Version2.0
Creation Date2014-09-05 17:10:06 UTC
Update Date2014-12-24 20:26:52 UTC
Accession NumberT3D4575
Identification
Common NamePyrocatechol
ClassSmall Molecule
DescriptionPyrocatechol, often known as catechol or benzene-1,2-diol, is a benzenediol, with formula C6H4(OH)2. It was first prepared in 1839 by H. Reinsch by distilling catechin (the juice of Mimosa catechu). This colourless compound occurs naturally, but about 20000 tons are manufactured each year, mainly as precursors to pesticides, flavors, and fragrances. Its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables, along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut), the colorless catechol oxidizes to reddish-brown benzoquinone derivatives. The enzyme is inactivated by adding an acid, such as lemon juice, or by refrigeration. Excluding oxygen also prevents the browning reaction. Catechol melts at 28 oC and boils at 250 oC. It is employed in medicine as an expectorant. The dimethyl ether or veratrol is also used in medicine. Many other pyrocatechin derivatives have been suggested for therapeutic application.
Compound Type
  • Cigarette Toxin
  • Food Toxin
  • Fragrance Toxin
  • Household Toxin
  • Metabolite
  • Organic Compound
  • Pesticide
  • Pollutant
  • Synthetic Compound
Chemical Structure
Thumb
Synonyms
Synonym
1,2-Dihydroxybenzene
2-Hydroxyphenol
Catechol
Durafur Developer C
Fouramine PCH
Fourrine 68
O-Benzenediol
O-Dihydroxybenzene
O-Dioxybenzene
O-Hydroquinone
O-Hydroxyphenol
O-Phenylenediol
Oxyphenate
Oxyphenic acid
Pelagol Grey C
Phthalhydroquinone
Phthalic alcohol
Pyrocatechin
Pyrocatechine
Chemical FormulaC6H6O2
Average Molecular Mass110.111 g/mol
Monoisotopic Mass110.037 g/mol
CAS Registry Number120-80-9
IUPAC Namebenzene-1,2-diol
Traditional Namecatechol
SMILESOC1=CC=CC=C1O
InChI IdentifierInChI=1S/C6H6O2/c7-5-3-1-2-4-6(5)8/h1-4,7-8H
InChI KeyInChIKey=YCIMNLLNPGFGHC-UHFFFAOYSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as catechols. Catechols are compounds containing a 1,2-benzenediol moiety.
KingdomOrganic compounds
Super ClassBenzenoids
ClassPhenols
Sub ClassBenzenediols
Direct ParentCatechols
Alternative Parents
Substituents
  • Catechol
  • 1-hydroxy-4-unsubstituted benzenoid
  • 1-hydroxy-2-unsubstituted benzenoid
  • Monocyclic benzene moiety
  • Organic oxygen compound
  • Hydrocarbon derivative
  • Organooxygen compound
  • Aromatic homomonocyclic compound
Molecular FrameworkAromatic homomonocyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Extracellular
Biofluid LocationsNot Available
Tissue Locations
  • Adipose Tissue
  • Adrenal Gland
  • Bone Marrow
  • Brain
  • Intestine
  • Liver
  • Neuron
  • Prostate
PathwaysNot Available
ApplicationsNot Available
Biological Roles
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceWhite powder.
Experimental Properties
PropertyValue
Melting Point105°C
Boiling Point245°C
Solubility4.61E+005 mg/L (at 25°C)
LogP0.88
Predicted Properties
PropertyValueSource
Water Solubility75 g/LALOGPS
logP0.74ALOGPS
logP1.37ChemAxon
logS-0.17ALOGPS
pKa (Strongest Acidic)9.34ChemAxon
pKa (Strongest Basic)-6.3ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area40.46 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity30.02 m³·mol⁻¹ChemAxon
Polarizability10.69 ųChemAxon
Number of Rings1ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyDeposition DateView
GC-MSGC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (Non-derivatized)splash10-0udr-1950000000-16187bb35dcb40c26e782014-06-16View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-03di-8900000000-4e15f35dca47661de5902017-09-12View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-03di-9600000000-032a40483dec937380752017-09-12View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-03di-7900000000-83f892852c355a3863e92017-09-12View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-03di-9400000000-90885264baa17f65d9542017-09-12View Spectrum
GC-MSGC-MS Spectrum - GC-EI-TOF (Non-derivatized)splash10-0udr-1950000000-16187bb35dcb40c26e782017-09-12View Spectrum
GC-MSGC-MS Spectrum - GC-EI-TOF (Non-derivatized)splash10-0udr-1930000000-24d2e0a8e36245d9e1872017-09-12View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-03di-7900000000-8b112b8af75eb2d086762017-07-27View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (2 TMS) - 70eV, Positivesplash10-0fl9-9730000000-a35befff1c602124f29e2017-10-06View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TMS_1_1) - 70eV, PositiveNot Available2021-11-06View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TBDMS_1_1) - 70eV, PositiveNot Available2021-11-06View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (TBDMS_2_1) - 70eV, PositiveNot Available2021-11-06View Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)splash10-01ox-9400000000-d59dce8c5e56b026f8b22012-07-24View Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)splash10-014i-9000000000-632cabc9b371835019c12012-07-24View Spectrum
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)splash10-02t9-9200000000-ac902cb99981017de3b52012-07-24View Spectrum
LC-MS/MSLC-MS/MS Spectrum - EI-B (VARIAN MAT-44) , Positivesplash10-03di-8900000000-95af3d2738de98d27f262012-08-31View Spectrum
LC-MS/MSLC-MS/MS Spectrum - EI-B (Unknown) , Positivesplash10-03di-9600000000-032a40483dec937380752012-08-31View Spectrum
LC-MS/MSLC-MS/MS Spectrum - EI-B (HITACHI M-80) , Positivesplash10-03di-7900000000-f5cb1c53768e05ca15302012-08-31View Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Negativesplash10-0a4i-0900000000-c94dab4d218dbb3bb1082012-08-31View Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) 30V, Negativesplash10-0a4i-1900000000-edd8ba1e77bbb2f763042012-08-31View Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0a4i-0900000000-c94dab4d218dbb3bb1082017-09-14View Spectrum
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0a4i-1900000000-edd8ba1e77bbb2f763042017-09-14View Spectrum
LC-MS/MSLC-MS/MS Spectrum - , negativesplash10-0a4i-0900000000-12053747e62e910151ad2017-09-14View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0900000000-72e952ea8e487994be542021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0900000000-19b1bae28f3dfde3323a2021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 30V, Negativesplash10-0006-9000000000-33b2a7e7a951547dfafa2021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0900000000-6e731d4eaba18fcad18f2021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 40V, Negativesplash10-0a4i-1900000000-a7c1a830ea96e82252bf2021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0900000000-3772b2cca96bf4a1b05f2021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0900000000-9531f3e0c85e67d6c6ed2021-09-20View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 20V, Negativesplash10-0a4i-1900000000-5886b926a1814092c4b12021-09-20View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-03di-0900000000-66523f3122b954e6400f2015-05-26View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-03di-1900000000-5fd776e479836f7464af2015-05-26View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0udi-9000000000-2c46a1375dbb634ef7352015-05-26View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0a4i-0900000000-986c93875cb12d90fa902015-05-27View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0a4i-0900000000-a301685abb4194689ca32015-05-27View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0a4i-9500000000-2017b42835ace86f16ee2015-05-27View Spectrum
MSMass Spectrum (Electron Ionization)splash10-03di-9600000000-b8e03f4f3ea89044828e2014-09-20View Spectrum
1D NMR1H NMR Spectrum (1D, 600 MHz, H2O, experimental)Not Available2012-12-04View Spectrum
1D NMR1H NMR Spectrum (1D, 100 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 100 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 200 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 200 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 300 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 300 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 400 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 400 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 500 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 500 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 600 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 600 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 700 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 700 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 800 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 800 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 900 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 900 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR1H NMR Spectrum (1D, 1000 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
1D NMR13C NMR Spectrum (1D, 1000 MHz, D2O, predicted)Not Available2021-09-16View Spectrum
2D NMR[1H, 13C]-HSQC NMR Spectrum (2D, 600 MHz, H2O, experimental)Not Available2012-12-05View Spectrum
Toxicity Profile
Route of ExposureNot Available
Mechanism of ToxicityNot Available
MetabolismNot Available
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)2B, possibly carcinogenic to humans. (22)
Uses/SourcesThis is a man-made compound that is used as a pesticide.
Minimum Risk LevelNot Available
Health EffectsNot Available
SymptomsNot Available
TreatmentNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDDB02232
HMDB IDHMDB00957
PubChem Compound ID289
ChEMBL IDNot Available
ChemSpider ID13837760
KEGG IDC00090
UniProt IDNot Available
OMIM ID
ChEBI ID18135
BioCyc IDCATECHOL
CTD IDNot Available
Stitch IDNot Available
PDB IDCAQ
ACToR IDNot Available
Wikipedia LinkPyrocatechol
References
Synthesis ReferenceNot Available
MSDSLink
General References
  1. Nguyen SD, Sok DE: Effect of 3,4-dihydroxyphenylalanine on Cu(2+)-induced inactivation of HDL-associated paraoxonasel and oxidation of HDL; inactivation of paraoxonasel activity independent of HDL lipid oxidation. Free Radic Res. 2004 Sep;38(9):969-76. [15621715 ]
  2. Kiso Y: Antioxidative roles of sesamin, a functional lignan in sesame seed, and it's effect on lipid- and alcohol-metabolism in the liver: a DNA microarray study. Biofactors. 2004;21(1-4):191-6. [15630196 ]
  3. Rivest J, Barclay CL, Suchowersky O: COMT inhibitors in Parkinson's disease. Can J Neurol Sci. 1999 Aug;26 Suppl 2:S34-8. [10451758 ]
  4. Goodall M, Diddle AW: Epinephrine and norepinephrine in pregnancy. A comparative study of the adrenal gland and catechol output in different species of animals and man. Am J Obstet Gynecol. 1971 Dec 1;111(7):896-904. [5118028 ]
  5. Olanow CW, Obeso JA: Pulsatile stimulation of dopamine receptors and levodopa-induced motor complications in Parkinson's disease: implications for the early use of COMT inhibitors. Neurology. 2000;55(11 Suppl 4):S72-7; discussion S78-81. [11147513 ]
  6. Zand R, Nelson SD, Slattery JT, Thummel KE, Kalhorn TF, Adams SP, Wright JM: Inhibition and induction of cytochrome P4502E1-catalyzed oxidation by isoniazid in humans. Clin Pharmacol Ther. 1993 Aug;54(2):142-9. [8354023 ]
  7. Swaminath G, Deupi X, Lee TW, Zhu W, Thian FS, Kobilka TS, Kobilka B: Probing the beta2 adrenoceptor binding site with catechol reveals differences in binding and activation by agonists and partial agonists. J Biol Chem. 2005 Jun 10;280(23):22165-71. Epub 2005 Apr 7. [15817484 ]
  8. Habecker BA, Willison BD, Shi X, Woodward WR: Chronic depolarization stimulates norepinephrine transporter expression via catecholamines. J Neurochem. 2006 May;97(4):1044-51. Epub 2006 Mar 29. [16573647 ]
  9. Goldstein DS, Holmes C, Kaufmann H, Freeman R: Clinical pharmacokinetics of the norepinephrine precursor L-threo-DOPS in primary chronic autonomic failure. Clin Auton Res. 2004 Dec;14(6):363-8. [15666063 ]
  10. Schapira AH, Obeso JA, Olanow CW: The place of COMT inhibitors in the armamentarium of drugs for the treatment of Parkinson's disease. Neurology. 2000;55(11 Suppl 4):S65-8; discussion S69-71. [11147512 ]
  11. Purba HS, Maggs JL, Orme ML, Back DJ, Park BK: The metabolism of 17 alpha-ethinyloestradiol by human liver microsomes: formation of catechol and chemically reactive metabolites. Br J Clin Pharmacol. 1987 Apr;23(4):447-53. [3555579 ]
  12. Moretti M, Villarini M, Simonucci S, Fatigoni C, Scassellati-Sforzolini G, Monarca S, Pasquini R, Angelucci M, Strappini M: Effects of co-exposure to extremely low frequency (ELF) magnetic fields and benzene or benzene metabolites determined in vitro by the alkaline comet assay. Toxicol Lett. 2005 Jun 17;157(2):119-28. [15836999 ]
  13. Poupaert J, Carato P, Colacino E, Yous S: 2(3H)-benzoxazolone and bioisosters as "privileged scaffold" in the design of pharmacological probes. Curr Med Chem. 2005;12(7):877-85. [15853716 ]
  14. Mosca L, Lendaro E, d'Erme M, Marcellini S, Moretti S, Rosei MA: 5-S-Cysteinyl-dopamine effect on the human dopaminergic neuroblastoma cell line SH-SY5Y. Neurochem Int. 2006 Aug;49(3):262-9. Epub 2006 Mar 20. [16549224 ]
  15. Santens P: Sleep attacks in Parkinson's disease induced by Entacapone, a COMT-inhibitor. Fundam Clin Pharmacol. 2003 Feb;17(1):121-3. [12588639 ]
  16. Cavalieri EL, Rogan EG, Chakravarti D: Initiation of cancer and other diseases by catechol ortho-quinones: a unifying mechanism. Cell Mol Life Sci. 2002 Apr;59(4):665-81. [12022473 ]
  17. Relling MV, Nemec J, Schuetz EG, Schuetz JD, Gonzalez FJ, Korzekwa KR: O-demethylation of epipodophyllotoxins is catalyzed by human cytochrome P450 3A4. Mol Pharmacol. 1994 Feb;45(2):352-8. [8114683 ]
  18. Irons RD: Quinones as toxic metabolites of benzene. J Toxicol Environ Health. 1985;16(5):673-8. [4093989 ]
  19. Luffer-Atlas D, Vincent SH, Painter SK, Arison BH, Stearns RA, Chiu SH: Orally active inhibitors of human leukocyte elastase. III. Identification and characterization of metabolites of L-694,458 by liquid chromatography-tandem mass spectrometry. Drug Metab Dispos. 1997 Aug;25(8):940-52. [9280402 ]
  20. Munns AJ, De Voss JJ, Hooper WD, Dickinson RG, Gillam EM: Bioactivation of phenytoin by human cytochrome P450: characterization of the mechanism and targets of covalent adduct formation. Chem Res Toxicol. 1997 Sep;10(9):1049-58. [9305589 ]
  21. Halliwell, Barry B., and Henrik E. Poulsen (2006). Cigarette Smoke and Oxidative Stress. Berlin: Springer. [ISBN: 978-3-540-31410-3 (Print) 978-3-540-32232-0 (Online)]
  22. International Agency for Research on Cancer (2014). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. [Link]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available

Targets

General Function:
Zinc ion binding
Specific Function:
Nuclear receptor that binds DNA as a monomer to ROR response elements (RORE) containing a single core motif half-site 5'-AGGTCA-3' preceded by a short A-T-rich sequence. Key regulator of cellular differentiation, immunity, peripheral circadian rhythm as well as lipid, steroid, xenobiotics and glucose metabolism. Considered to have intrinsic transcriptional activity, have some natural ligands like oxysterols that act as agonists (25-hydroxycholesterol) or inverse agonists (7-oxygenated sterols), enhancing or repressing the transcriptional activity, respectively. Recruits distinct combinations of cofactors to target gene regulatory regions to modulate their transcriptional expression, depending on the tissue, time and promoter contexts. Regulates the circadian expression of clock genes such as CRY1, ARNTL/BMAL1 and NR1D1 in peripheral tissues and in a tissue-selective manner. Competes with NR1D1 for binding to their shared DNA response element on some clock genes such as ARNTL/BMAL1, CRY1 and NR1D1 itself, resulting in NR1D1-mediated repression or RORC-mediated activation of the expression, leading to the circadian pattern of clock genes expression. Therefore influences the period length and stability of the clock. Involved in the regulation of the rhythmic expression of genes involved in glucose and lipid metabolism, including PLIN2 and AVPR1A. Negative regulator of adipocyte differentiation through the regulation of early phase genes expression, such as MMP3. Controls adipogenesis as well as adipocyte size and modulates insulin sensitivity in obesity. In liver, has specific and redundant functions with RORA as positive or negative modulator of expression of genes encoding phase I and Phase II proteins involved in the metabolism of lipids, steroids and xenobiotics, such as SULT1E1. Also plays also a role in the regulation of hepatocyte glucose metabolism through the regulation of G6PC and PCK1. Regulates the rhythmic expression of PROX1 and promotes its nuclear localization (By similarity). Plays an indispensable role in the induction of IFN-gamma dependent anti-mycobacterial systemic immunity (PubMed:26160376).Isoform 2: Essential for thymopoiesis and the development of several secondary lymphoid tissues, including lymph nodes and Peyer's patches. Required for the generation of LTi (lymphoid tissue inducer) cells. Regulates thymocyte survival through DNA-binding on ROREs of target gene promoter regions and recruitment of coactivaros via the AF-2. Also plays a key role, downstream of IL6 and TGFB and synergistically with RORA, for lineage specification of uncommitted CD4(+) T-helper (T(H)) cells into T(H)17 cells, antagonizing the T(H)1 program. Probably regulates IL17 and IL17F expression on T(H) by binding to the essential enhancer conserved non-coding sequence 2 (CNS2) in the IL17-IL17F locus. May also play a role in the pre-TCR activation cascade leading to the maturation of alpha/beta T-cells and may participate in the regulation of DNA accessibility in the TCR-J(alpha) locus.
Gene Name:
RORC
Uniprot ID:
P51449
Molecular Weight:
58194.845 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
AC501.31 uMATG_RORg_TRANSAttagene
References
  1. Sipes NS, Martin MT, Kothiya P, Reif DM, Judson RS, Richard AM, Houck KA, Dix DJ, Kavlock RJ, Knudsen TB: Profiling 976 ToxCast chemicals across 331 enzymatic and receptor signaling assays. Chem Res Toxicol. 2013 Jun 17;26(6):878-95. doi: 10.1021/tx400021f. Epub 2013 May 16. [23611293 ]