Hmdb loader
You are using an unsupported browser. Please upgrade your browser to a newer version to get the best experience on Human Metabolome Database.
Record Information
Version5.0
StatusDetected and Quantified
Creation Date2006-02-22 11:10:26 UTC
Update Date2021-09-07 16:45:31 UTC
HMDB IDHMDB0001860
Secondary Accession Numbers
  • HMDB01860
Metabolite Identification
Common NameParaxanthine
DescriptionParaxanthine, also known as p-xanthine, belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety. Paraxanthine exists in all living organisms, ranging from bacteria to humans. Within humans, paraxanthine participates in a number of enzymatic reactions. In particular, paraxanthine and formaldehyde can be biosynthesized from caffeine; which is catalyzed by the enzyme cytochrome P450 1A2. In addition, paraxanthine and acetyl-CoA can be converted into 5-acetylamino-6-formylamino-3-methyluracil through its interaction with the enzyme arylamine N-acetyltransferase 2. In humans, paraxanthine is involved in caffeine metabolism.
Structure
Data?1582752213
Synonyms
ValueSource
3,7-Dihydro-1,7-dimethyl-1H-purine-2,6-dioneChEBI
p-XanthineChEBI
1,7-Dimethyl-xanthineHMDB
1,7-DimethylxanthineHMDB, MeSH
Chemical FormulaC7H8N4O2
Average Molecular Weight180.164
Monoisotopic Molecular Weight180.06472552
IUPAC Name1,7-dimethyl-2,3,6,7-tetrahydro-1H-purine-2,6-dione
Traditional Nameparaxanthine
CAS Registry Number611-59-6
SMILES
CN1C=NC2=C1C(=O)N(C)C(=O)N2
InChI Identifier
InChI=1S/C7H8N4O2/c1-10-3-8-5-4(10)6(12)11(2)7(13)9-5/h3H,1-2H3,(H,9,13)
InChI KeyQUNWUDVFRNGTCO-UHFFFAOYSA-N
Chemical Taxonomy
Description Belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassImidazopyrimidines
Sub ClassPurines and purine derivatives
Direct ParentXanthines
Alternative Parents
Substituents
  • Xanthine
  • 6-oxopurine
  • Purinone
  • Alkaloid or derivatives
  • Pyrimidone
  • Hydroxypyrimidine
  • N-substituted imidazole
  • Pyrimidine
  • Imidazole
  • Azole
  • Heteroaromatic compound
  • Lactam
  • Azacycle
  • Hydrocarbon derivative
  • Organic oxide
  • Organopnictogen compound
  • Organic oxygen compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organic nitrogen compound
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptors
Ontology
Physiological effect

Adverse health effect

Disposition

Biological location

Source

Route of exposure

Process

Naturally occurring process

Physical Properties
StateSolid
Experimental Molecular Properties
PropertyValueReference
Melting Point351 - 352 °CNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Experimental Chromatographic Properties

Experimental Collision Cross Sections

Adduct TypeData SourceCCS Value (Å2)Reference
[M+H]+Baker135.62530932474
[M-H]-Not Available133.24http://allccs.zhulab.cn/database/detail?ID=AllCCS00000345
[M+H]+Not Available135.625http://allccs.zhulab.cn/database/detail?ID=AllCCS00000345
Predicted Molecular Properties
PropertyValueSource
Water Solubility9.13 g/LALOGPS
logP10(-0.63) g/LALOGPS
logP10(0.24) g/LChemAxon
logS10(-1.3) g/LALOGPS
pKa (Strongest Acidic)10.76ChemAxon
pKa (Strongest Basic)-0.87ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area67.23 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity46.72 m³·mol⁻¹ChemAxon
Polarizability16.87 ųChemAxon
Number of Rings2ChemAxon
BioavailabilityYesChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Predicted Chromatographic Properties

Predicted Collision Cross Sections

PredictorAdduct TypeCCS Value (Å2)Reference
DarkChem[M+H]+140.38531661259
DarkChem[M-H]-137.3631661259
AllCCS[M+H]+138.46732859911
AllCCS[M-H]-136.81132859911
DeepCCS[M+H]+134.44230932474
DeepCCS[M-H]-131.85630932474

Predicted Kovats Retention Indices

Underivatized

MetaboliteSMILESKovats RI ValueColumn TypeReference
ParaxanthineCN1C=NC2=C1C(=O)N(C)C(=O)N22382.3Standard polar33892256
ParaxanthineCN1C=NC2=C1C(=O)N(C)C(=O)N21867.7Standard non polar33892256
ParaxanthineCN1C=NC2=C1C(=O)N(C)C(=O)N22065.8Semi standard non polar33892256

Derivatized

Derivative Name / StructureSMILESKovats RI ValueColumn TypeReference
Paraxanthine,1TMS,isomer #1CN1C(=O)C2=C(N=CN2C)N([Si](C)(C)C)C1=O1875.3Semi standard non polar33892256
Paraxanthine,1TMS,isomer #1CN1C(=O)C2=C(N=CN2C)N([Si](C)(C)C)C1=O2088.9Standard non polar33892256
Paraxanthine,1TMS,isomer #1CN1C(=O)C2=C(N=CN2C)N([Si](C)(C)C)C1=O2612.9Standard polar33892256
Paraxanthine,1TBDMS,isomer #1CN1C(=O)C2=C(N=CN2C)N([Si](C)(C)C(C)(C)C)C1=O2095.9Semi standard non polar33892256
Paraxanthine,1TBDMS,isomer #1CN1C(=O)C2=C(N=CN2C)N([Si](C)(C)C(C)(C)C)C1=O2279.3Standard non polar33892256
Paraxanthine,1TBDMS,isomer #1CN1C(=O)C2=C(N=CN2C)N([Si](C)(C)C(C)(C)C)C1=O2605.4Standard polar33892256
Spectra

GC-MS Spectra

Spectrum TypeDescriptionSplash KeyDeposition DateSourceView
Experimental GC-MSGC-MS Spectrum - Paraxanthine GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (Non-derivatized)splash10-000i-2980000000-6ee5dc3100885f2055362014-06-16HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - Paraxanthine GC-EI-TOF (Non-derivatized)splash10-000i-2980000000-6ee5dc3100885f2055362017-09-12HMDB team, MONA, MassBankView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - Paraxanthine GC-MS (Non-derivatized) - 70eV, Positivesplash10-0uka-3900000000-d979badf45de391835d42017-09-01Wishart LabView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - Paraxanthine GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12Wishart LabView Spectrum

MS/MS Spectra

Spectrum TypeDescriptionSplash KeyDeposition DateSourceView
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Quattro_QQQ 10V, Positive-QTOF (Annotated)splash10-001i-0900000000-2d1aa5f80618f452686c2012-07-24HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Quattro_QQQ 25V, Positive-QTOF (Annotated)splash10-00di-0900000000-3326bcbee23b63dcc2302012-07-24HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Quattro_QQQ 40V, Positive-QTOF (Annotated)splash10-014l-9000000000-9824aef9dc2f13c24bcc2012-07-24HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Positive-QTOFsplash10-00e9-1900000000-9d0dde13bb1ce13e26442012-08-31HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Negative-QTOFsplash10-00fr-0900000000-1aa733a1b7e41b994d8d2012-08-31HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine LC-ESI-qTof , Positive-QTOFsplash10-00di-1900000000-190ff3302e9f5a37a72f2017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine LC-ESI-QTOF , negative-QTOFsplash10-00fr-0900000000-1aa733a1b7e41b994d8d2017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Linear Ion Trap , negative-QTOFsplash10-0229-0900000000-729a2bed81ba15260ffa2017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Linear Ion Trap , negative-QTOFsplash10-0229-0900000000-18d0a9c63a1dfb683c9b2017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine , negative-QTOFsplash10-004i-0900000000-c52421f0ba1f462418532017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine LC-ESI-IT , positive-QTOFsplash10-00di-0900000000-0bd6ed3d764e5a9b374e2017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine LC-ESI-QTOF , positive-QTOFsplash10-00e9-1900000000-9d0dde13bb1ce13e26442017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Linear Ion Trap , positive-QTOFsplash10-0w29-0940000000-127f99d8e7324e01eb662017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine Linear Ion Trap , positive-QTOFsplash10-0ik9-0930000000-fe234438cbe3be0b30f62017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine , positive-QTOFsplash10-00di-1900000000-190ff3302e9f5a37a72f2017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine , positive-QTOFsplash10-001i-0900000000-d6040ea84fe19d8c5cc62017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine 10V, Positive-QTOFsplash10-001i-0900000000-935e5a47dc1abe7b11962021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine 35V, Positive-QTOFsplash10-00di-3900000000-2f3998477ce19f3ff96f2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Paraxanthine 20V, Positive-QTOFsplash10-00di-4900000000-c89111b73e8a9a1631112021-09-20HMDB team, MONAView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Paraxanthine 10V, Positive-QTOFsplash10-001i-0900000000-5e7c398698bb5c16617d2017-09-01Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Paraxanthine 20V, Positive-QTOFsplash10-00di-1900000000-522eaddc21ef92e70e622017-09-01Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Paraxanthine 40V, Positive-QTOFsplash10-0005-9200000000-d10a1141c0e21f56ec002017-09-01Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Paraxanthine 10V, Negative-QTOFsplash10-004i-1900000000-bc2d3cb520a4fcb815292017-09-01Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Paraxanthine 20V, Negative-QTOFsplash10-004i-2900000000-e2e2992ce9b1265af7902017-09-01Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Paraxanthine 40V, Negative-QTOFsplash10-05am-9300000000-e1aefedceb8692ffe91f2017-09-01Wishart LabView Spectrum

NMR Spectra

Spectrum TypeDescriptionDeposition DateSourceView
Experimental 1D NMR1H NMR Spectrum (1D, 500 MHz, H2O, experimental)2012-12-04Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 100 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 100 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 1000 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 1000 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 200 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 200 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 300 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 300 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 400 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 400 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 500 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 500 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 600 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 600 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 700 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 700 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 800 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 800 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 900 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 900 MHz, D2O, predicted)2021-09-29Wishart LabView Spectrum
Experimental 2D NMR[1H, 13C]-HSQC NMR Spectrum (2D, 600 MHz, H2O, experimental)2012-12-05Wishart LabView Spectrum
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biospecimen Locations
  • Blood
  • Cerebrospinal Fluid (CSF)
  • Feces
  • Saliva
  • Urine
Tissue Locations
  • Kidney
  • Liver
  • Placenta
  • Prostate
Pathways
Normal Concentrations
BiospecimenStatusValueAgeSexConditionReferenceDetails
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothNormal details
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
BloodDetected and Quantified10.0 (0.30-28.0) uMAdult (>18 years old)BothNormal details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Not SpecifiedNormal details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Male
Normal
details
UrineDetected and Quantified3.44 +/- 2 umol/mmol creatinineChildren (1 - 13 years old)Not Specified
Normal
    • Analysis of 30 no...
details
UrineDetected and Quantified2.5 (3.2-4.0) umol/mmol creatinineAdult (>18 years old)BothNormal details
UrineDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothNormal details
Abnormal Concentrations
BiospecimenStatusValueAgeSexConditionReferenceDetails
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Colorectal adenoma
details
Cerebrospinal Fluid (CSF)Detected and Quantified1.780 +/- 0.641 uMAdult (>18 years old)Not SpecifiedFavorable outcome from traumatic brain injury details
Cerebrospinal Fluid (CSF)Detected and Quantified0.833 +/- 1.163 uMAdult (>18 years old)MaleTraumatic Brain Injury (TBI) details
Cerebrospinal Fluid (CSF)Detected and Quantified1.200 +/- 1.373 uMAdult (>18 years old)FemaleTraumatic Brain Injury (TBI) details
Cerebrospinal Fluid (CSF)Detected and Quantified0.703 +/- 0.230 uMAdult (>18 years old)Not Specified
Traumatic brain injury
details
Cerebrospinal Fluid (CSF)Detected and Quantified0.931 +/- 0.221 uMAdult (>18 years old)Not SpecifiedTraumatic brain injury (TBI) details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Colorectal cancer
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothColorectal Cancer details
UrineDetected and Quantified18.676 +/- 26.196 umol/mmol creatinineChildren (1 - 13 years old)Not Specified
Eosinophilic esophagitis
    • Analysis of 30 no...
details
UrineDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Colorectal adenoma
details
UrineDetected and Quantified3.6 (1.8-5.4) umol/mmol creatinineAdult (>18 years old)Both
Asthma
details
Associated Disorders and Diseases
Disease References
Traumatic brain injury
  1. Sachse KT, Jackson EK, Wisniewski SR, Gillespie DG, Puccio AM, Clark RS, Dixon CE, Kochanek PM: Increases in cerebrospinal fluid caffeine concentration are associated with favorable outcome after severe traumatic brain injury in humans. J Cereb Blood Flow Metab. 2008 Feb;28(2):395-401. Epub 2007 Aug 8. [PubMed:17684518 ]
Head injury
  1. Sachse KT, Jackson EK, Wisniewski SR, Gillespie DG, Puccio AM, Clark RS, Dixon CE, Kochanek PM: Increases in cerebrospinal fluid caffeine concentration are associated with favorable outcome after severe traumatic brain injury in humans. J Cereb Blood Flow Metab. 2008 Feb;28(2):395-401. Epub 2007 Aug 8. [PubMed:17684518 ]
Colorectal cancer
  1. Brown DG, Rao S, Weir TL, O'Malia J, Bazan M, Brown RJ, Ryan EP: Metabolomics and metabolic pathway networks from human colorectal cancers, adjacent mucosa, and stool. Cancer Metab. 2016 Jun 6;4:11. doi: 10.1186/s40170-016-0151-y. eCollection 2016. [PubMed:27275383 ]
  2. Goedert JJ, Sampson JN, Moore SC, Xiao Q, Xiong X, Hayes RB, Ahn J, Shi J, Sinha R: Fecal metabolomics: assay performance and association with colorectal cancer. Carcinogenesis. 2014 Sep;35(9):2089-96. doi: 10.1093/carcin/bgu131. Epub 2014 Jul 18. [PubMed:25037050 ]
Asthma
  1. Zydron M, Baranowski J, Baranowska I: Separation, pre-concentration, and HPLC analysis of methylxanthines in urine samples. J Sep Sci. 2004 Oct;27(14):1166-72. [PubMed:15537072 ]
Eosinophilic esophagitis
  1. Slae, M., Huynh, H., Wishart, D.S. (2014). Analysis of 30 normal pediatric urine samples via NMR spectroscopy (unpublished work). NA.
Associated OMIM IDs
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FooDB IDFDB022714
KNApSAcK IDC00039930
Chemspider ID4525
KEGG Compound IDC13747
BioCyc ID1-7-DIMETHYLXANTHINE
BiGG IDNot Available
Wikipedia LinkParaxanthine
METLIN ID1457
PubChem Compound4687
PDB IDNot Available
ChEBI ID25858
Food Biomarker OntologyNot Available
VMH IDNot Available
MarkerDB IDNot Available
Good Scents IDNot Available
References
Synthesis ReferenceMueller, Christa E.; Deters, Dirk; Dominik, Andreas; Pawlowski, Maciej. Synthesis of paraxanthine and isoparaxanthine analogs (1,7- and 1,9-substituted xanthine derivatives). Synthesis (1998), (10), 1428-1436.
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Sreekumar A, Poisson LM, Rajendiran TM, Khan AP, Cao Q, Yu J, Laxman B, Mehra R, Lonigro RJ, Li Y, Nyati MK, Ahsan A, Kalyana-Sundaram S, Han B, Cao X, Byun J, Omenn GS, Ghosh D, Pennathur S, Alexander DC, Berger A, Shuster JR, Wei JT, Varambally S, Beecher C, Chinnaiyan AM: Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression. Nature. 2009 Feb 12;457(7231):910-4. doi: 10.1038/nature07762. [PubMed:19212411 ]
  2. Christensen M, Andersson K, Dalen P, Mirghani RA, Muirhead GJ, Nordmark A, Tybring G, Wahlberg A, Yasar U, Bertilsson L: The Karolinska cocktail for phenotyping of five human cytochrome P450 enzymes. Clin Pharmacol Ther. 2003 Jun;73(6):517-28. [PubMed:12811361 ]
  3. Fuhr U, Rost KL: Simple and reliable CYP1A2 phenotyping by the paraxanthine/caffeine ratio in plasma and in saliva. Pharmacogenetics. 1994 Jun;4(3):109-16. [PubMed:7920690 ]
  4. Tanaka E: Simultaneous determination of caffeine and its primary demethylated metabolites in human plasma by high-performance liquid chromatography. J Chromatogr. 1992 Mar 27;575(2):311-4. [PubMed:1629311 ]
  5. Horrigan LA, Kelly JP, Connor TJ: Immunomodulatory effects of caffeine: friend or foe? Pharmacol Ther. 2006 Sep;111(3):877-92. Epub 2006 Mar 15. [PubMed:16540173 ]
  6. Holstege A, Kurz M, Weinbeck M, Gerok W: Excretion of caffeine and its primary degradation products into bile. J Hepatol. 1993 Jan;17(1):67-73. [PubMed:8445222 ]
  7. Granfors MT, Backman JT, Laitila J, Neuvonen PJ: Oral contraceptives containing ethinyl estradiol and gestodene markedly increase plasma concentrations and effects of tizanidine by inhibiting cytochrome P450 1A2. Clin Pharmacol Ther. 2005 Oct;78(4):400-11. [PubMed:16198659 ]
  8. Blanchard J, Weber CW, Shearer LE: HPLC analysis of methylxanthines in human breast milk. J Chromatogr Sci. 1990 Dec;28(12):640-2. [PubMed:2292610 ]
  9. Delahunty T, Schoendorfer D: Caffeine demethylation monitoring using a transdermal sweat patch. J Anal Toxicol. 1998 Nov-Dec;22(7):596-600. [PubMed:9847011 ]
  10. Holland DT, Godfredsen KA, Page T, Connor JD: Simple high-performance liquid chromatography method for the simultaneous determination of serum caffeine and paraxanthine following rapid sample preparation. J Chromatogr B Biomed Sci Appl. 1998 Apr 10;707(1-2):105-10. [PubMed:9613939 ]
  11. Fuhr U, Rost KL, Engelhardt R, Sachs M, Liermann D, Belloc C, Beaune P, Janezic S, Grant D, Meyer UA, Staib AH: Evaluation of caffeine as a test drug for CYP1A2, NAT2 and CYP2E1 phenotyping in man by in vivo versus in vitro correlations. Pharmacogenetics. 1996 Apr;6(2):159-76. [PubMed:9156694 ]
  12. Zaigler M, Rietbrock S, Szymanski J, Dericks-Tan JS, Staib AH, Fuhr U: Variation of CYP1A2-dependent caffeine metabolism during menstrual cycle in healthy women. Int J Clin Pharmacol Ther. 2000 May;38(5):235-44. [PubMed:10839467 ]
  13. Blanchard J, Weber CW, Shearer LE: Methylxanthine levels in breast milk of lactating women of different ethnic and socioeconomic classes. Biopharm Drug Dispos. 1992 Apr;13(3):187-96. [PubMed:1576327 ]
  14. Wahllander A, Renner E, Karlaganis G: High-performance liquid chromatographic determination of dimethylxanthine metabolites of caffeine in human plasma. J Chromatogr. 1985 Mar 22;338(2):369-75. [PubMed:3998024 ]
  15. Koch JP, ten Tusscher GW, Koppe JG, Guchelaar HJ: Validation of a high-performance liquid chromatography assay for quantification of caffeine and paraxanthine in human serum in the context of CYP1A2 phenotyping. Biomed Chromatogr. 1999 Jun;13(4):309-14. [PubMed:10416066 ]
  16. Sachse C, Ruschen S, Dettling M, Schley J, Bauer S, Muller-Oerlinghausen B, Roots I, Brockmoller J: Flavin monooxygenase 3 (FMO3) polymorphism in a white population: allele frequencies, mutation linkage, and functional effects on clozapine and caffeine metabolism. Clin Pharmacol Ther. 1999 Oct;66(4):431-8. [PubMed:10546928 ]
  17. Elshenawy S, Pinney SE, Stuart T, Doulias PT, Zura G, Parry S, Elovitz MA, Bennett MJ, Bansal A, Strauss JF 3rd, Ischiropoulos H, Simmons RA: The Metabolomic Signature of the Placenta in Spontaneous Preterm Birth. Int J Mol Sci. 2020 Feb 4;21(3). pii: ijms21031043. doi: 10.3390/ijms21031043. [PubMed:32033212 ]

Only showing the first 10 proteins. There are 28 proteins in total.

Enzymes

General function:
Involved in acetyltransferase activity
Specific function:
Participates in the detoxification of a plethora of hydrazine and arylamine drugs. Catalyzes the N- or O-acetylation of various arylamine and heterocyclic amine substrates and is able to bioactivate several known carcinogens.
Gene Name:
NAT1
Uniprot ID:
P18440
Molecular weight:
33898.445
Reactions
Paraxanthine → 5-Acetylamino-6-formylamino-3-methyluracildetails
General function:
Involved in acetyltransferase activity
Specific function:
Participates in the detoxification of a plethora of hydrazine and arylamine drugs. Catalyzes the N- or O-acetylation of various arylamine and heterocyclic amine substrates and is able to bioactivate several known carcinogens.
Gene Name:
NAT2
Uniprot ID:
P11245
Molecular weight:
33570.245
Reactions
Paraxanthine → 5-Acetylamino-6-formylamino-3-methyluracildetails
General function:
Involved in oxidoreductase activity
Specific function:
Key enzyme in purine degradation. Catalyzes the oxidation of hypoxanthine to xanthine. Catalyzes the oxidation of xanthine to uric acid. Contributes to the generation of reactive oxygen species. Has also low oxidase activity towards aldehydes (in vitro).
Gene Name:
XDH
Uniprot ID:
P47989
Molecular weight:
146422.99
Reactions
Paraxanthine + Oxygen + Water → 1,7-Dimethyluric acid + Hydrogen peroxidedetails
General function:
Involved in monooxygenase activity
Specific function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It performs a variety of oxidation reactions (e.g. caffeine 8-oxidation, omeprazole sulphoxidation, midazolam 1'-hydroxylation and midazolam 4-hydroxylation) of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. Acts as a 1,8-cineole 2-exo-monooxygenase. The enzyme also hydroxylates etoposide.
Gene Name:
CYP3A4
Uniprot ID:
P08684
Molecular weight:
57255.585
General function:
Involved in monooxygenase activity
Specific function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. This enzyme contributes to the wide pharmacokinetics variability of the metabolism of drugs such as S-warfarin, diclofenac, phenytoin, tolbutamide and losartan.
Gene Name:
CYP2C9
Uniprot ID:
P11712
Molecular weight:
55627.365
General function:
Involved in monooxygenase activity
Specific function:
Responsible for the metabolism of a number of therapeutic agents such as the anticonvulsant drug S-mephenytoin, omeprazole, proguanil, certain barbiturates, diazepam, propranolol, citalopram and imipramine.
Gene Name:
CYP2C19
Uniprot ID:
P33261
Molecular weight:
55944.565
General function:
Involved in monooxygenase activity
Specific function:
Metabolizes several precarcinogens, drugs, and solvents to reactive metabolites. Inactivates a number of drugs and xenobiotics and also bioactivates many xenobiotic substrates to their hepatotoxic or carcinogenic forms.
Gene Name:
CYP2E1
Uniprot ID:
P05181
Molecular weight:
56848.42
General function:
Involved in monooxygenase activity
Specific function:
Exhibits low testosterone 6-beta-hydroxylase activity.
Gene Name:
CYP3A43
Uniprot ID:
Q9HB55
Molecular weight:
57756.285
General function:
Involved in monooxygenase activity
Specific function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. Participates in the metabolism of an as-yet-unknown biologically active molecule that is a participant in eye development.
Gene Name:
CYP1B1
Uniprot ID:
Q16678
Molecular weight:
60845.33
General function:
Involved in monooxygenase activity
Specific function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics.
Gene Name:
CYP2C18
Uniprot ID:
P33260
Molecular weight:
55710.075

Only showing the first 10 proteins. There are 28 proteins in total.