Hmdb loader
Record Information
Version5.0
StatusDetected and Quantified
Creation Date2006-05-22 15:12:26 UTC
Update Date2023-02-21 17:16:30 UTC
HMDB IDHMDB0003011
Secondary Accession Numbers
  • HMDB03011
Metabolite Identification
Common NameO-Acetylserine
DescriptionO-Acetylserine is an α-amino acid with the chemical formula HO2CCH(NH2)CH2OC(O)CH3. It is an intermediate in the biosynthesis of the common amino acid cysteine in bacteria and plants. O-Acetylserine is biosynthesized by acetylation of the serine by the enzyme serine transacetylase. The enzyme O-acetylserine (thiol)-lyase, using sulfide sources, converts this ester into cysteine, releasing acetate. O-Acetylserine belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. O-Acetylserine (OASS) is an acylated amino acid derivative. O-Acetylserine exists in all living species, ranging from bacteria to humans. Outside of the human body, O-Acetylserine has been detected, but not quantified in several different foods, such as okra, vaccinium (blueberry, cranberry, huckleberry), rapes, sparkleberries, and lingonberries. This could make O-acetylserine a potential biomarker for the consumption of these foods.
Structure
Data?1676999790
Synonyms
ValueSource
L-Serine, acetate (ester)ChEBI
O3-Acetyl-L-serineChEBI
L-Serine, acetic acid (ester)Generator
O-Acetyl-L-serineHMDB
O-Acetyl-serineHMDB
O-Acetylserine hydrobromide, (D)-isomerHMDB
O-Acetylserine, (L)-isomerHMDB
Serine acetate esterHMDB
O-AcetylserineMeSH
Chemical FormulaC5H9NO4
Average Molecular Weight147.1293
Monoisotopic Molecular Weight147.053157781
IUPAC Name(2S)-3-(acetyloxy)-2-aminopropanoic acid
Traditional NameO-acetyl-L-serine
CAS Registry Number5147-00-2
SMILES
CC(=O)OC[C@H](N)C(O)=O
InChI Identifier
InChI=1S/C5H9NO4/c1-3(7)10-2-4(6)5(8)9/h4H,2,6H2,1H3,(H,8,9)/t4-/m0/s1
InChI KeyVZXPDPZARILFQX-BYPYZUCNSA-N
Chemical Taxonomy
Description Belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentL-alpha-amino acids
Alternative Parents
Substituents
  • L-alpha-amino acid
  • Dicarboxylic acid or derivatives
  • Carboxylic acid ester
  • Amino acid
  • Carboxylic acid
  • Hydrocarbon derivative
  • Organopnictogen compound
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Primary aliphatic amine
  • Organic oxygen compound
  • Organic nitrogen compound
  • Carbonyl group
  • Amine
  • Organic oxide
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Ontology
Physiological effectNot Available
Disposition
Biological locationSource
Process
RoleNot Available
Physical Properties
StateSolid
Experimental Molecular Properties
PropertyValueReference
Melting PointNot AvailableNot 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]+Not Available130.4http://allccs.zhulab.cn/database/detail?ID=AllCCS00002164
Predicted Molecular Properties
PropertyValueSource
Water Solubility174 g/LALOGPS
logP-2.8ALOGPS
logP-3.4ChemAxon
logS0.07ALOGPS
pKa (Strongest Acidic)1.86ChemAxon
pKa (Strongest Basic)8.6ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area89.62 ŲChemAxon
Rotatable Bond Count4ChemAxon
Refractivity31.19 m³·mol⁻¹ChemAxon
Polarizability13.44 ųChemAxon
Number of Rings0ChemAxon
BioavailabilityYesChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Predicted Chromatographic Properties

Predicted Collision Cross Sections

PredictorAdduct TypeCCS Value (Å2)Reference
DarkChem[M+H]+131.14131661259
DarkChem[M-H]-126.16631661259
DeepCCS[M+H]+124.73130932474
DeepCCS[M-H]-120.9130932474
DeepCCS[M-2H]-158.31930932474
DeepCCS[M+Na]+133.67930932474
AllCCS[M+H]+134.032859911
AllCCS[M+H-H2O]+130.132859911
AllCCS[M+NH4]+137.732859911
AllCCS[M+Na]+138.832859911
AllCCS[M-H]-128.232859911
AllCCS[M+Na-2H]-130.532859911
AllCCS[M+HCOO]-133.132859911

Predicted Kovats Retention Indices

Underivatized

MetaboliteSMILESKovats RI ValueColumn TypeReference
O-AcetylserineCC(=O)OC[C@H](N)C(O)=O2083.6Standard polar33892256
O-AcetylserineCC(=O)OC[C@H](N)C(O)=O1179.0Standard non polar33892256
O-AcetylserineCC(=O)OC[C@H](N)C(O)=O1601.7Semi standard non polar33892256

Derivatized

Derivative Name / StructureSMILESKovats RI ValueColumn TypeReference
O-Acetylserine,1TMS,isomer #1CC(=O)OC[C@H](N)C(=O)O[Si](C)(C)C1281.9Semi standard non polar33892256
O-Acetylserine,1TMS,isomer #2CC(=O)OC[C@H](N[Si](C)(C)C)C(=O)O1368.8Semi standard non polar33892256
O-Acetylserine,2TMS,isomer #1CC(=O)OC[C@H](N[Si](C)(C)C)C(=O)O[Si](C)(C)C1418.8Semi standard non polar33892256
O-Acetylserine,2TMS,isomer #1CC(=O)OC[C@H](N[Si](C)(C)C)C(=O)O[Si](C)(C)C1444.1Standard non polar33892256
O-Acetylserine,2TMS,isomer #1CC(=O)OC[C@H](N[Si](C)(C)C)C(=O)O[Si](C)(C)C1796.7Standard polar33892256
O-Acetylserine,2TMS,isomer #2CC(=O)OC[C@@H](C(=O)O)N([Si](C)(C)C)[Si](C)(C)C1575.0Semi standard non polar33892256
O-Acetylserine,2TMS,isomer #2CC(=O)OC[C@@H](C(=O)O)N([Si](C)(C)C)[Si](C)(C)C1501.4Standard non polar33892256
O-Acetylserine,2TMS,isomer #2CC(=O)OC[C@@H](C(=O)O)N([Si](C)(C)C)[Si](C)(C)C1979.4Standard polar33892256
O-Acetylserine,3TMS,isomer #1CC(=O)OC[C@@H](C(=O)O[Si](C)(C)C)N([Si](C)(C)C)[Si](C)(C)C1620.1Semi standard non polar33892256
O-Acetylserine,3TMS,isomer #1CC(=O)OC[C@@H](C(=O)O[Si](C)(C)C)N([Si](C)(C)C)[Si](C)(C)C1550.2Standard non polar33892256
O-Acetylserine,3TMS,isomer #1CC(=O)OC[C@@H](C(=O)O[Si](C)(C)C)N([Si](C)(C)C)[Si](C)(C)C1740.6Standard polar33892256
O-Acetylserine,1TBDMS,isomer #1CC(=O)OC[C@H](N)C(=O)O[Si](C)(C)C(C)(C)C1507.0Semi standard non polar33892256
O-Acetylserine,1TBDMS,isomer #2CC(=O)OC[C@H](N[Si](C)(C)C(C)(C)C)C(=O)O1596.5Semi standard non polar33892256
O-Acetylserine,2TBDMS,isomer #1CC(=O)OC[C@H](N[Si](C)(C)C(C)(C)C)C(=O)O[Si](C)(C)C(C)(C)C1831.3Semi standard non polar33892256
O-Acetylserine,2TBDMS,isomer #1CC(=O)OC[C@H](N[Si](C)(C)C(C)(C)C)C(=O)O[Si](C)(C)C(C)(C)C1865.0Standard non polar33892256
O-Acetylserine,2TBDMS,isomer #1CC(=O)OC[C@H](N[Si](C)(C)C(C)(C)C)C(=O)O[Si](C)(C)C(C)(C)C2038.2Standard polar33892256
O-Acetylserine,2TBDMS,isomer #2CC(=O)OC[C@@H](C(=O)O)N([Si](C)(C)C(C)(C)C)[Si](C)(C)C(C)(C)C1985.8Semi standard non polar33892256
O-Acetylserine,2TBDMS,isomer #2CC(=O)OC[C@@H](C(=O)O)N([Si](C)(C)C(C)(C)C)[Si](C)(C)C(C)(C)C1924.8Standard non polar33892256
O-Acetylserine,2TBDMS,isomer #2CC(=O)OC[C@@H](C(=O)O)N([Si](C)(C)C(C)(C)C)[Si](C)(C)C(C)(C)C2119.2Standard polar33892256
O-Acetylserine,3TBDMS,isomer #1CC(=O)OC[C@@H](C(=O)O[Si](C)(C)C(C)(C)C)N([Si](C)(C)C(C)(C)C)[Si](C)(C)C(C)(C)C2249.6Semi standard non polar33892256
O-Acetylserine,3TBDMS,isomer #1CC(=O)OC[C@@H](C(=O)O[Si](C)(C)C(C)(C)C)N([Si](C)(C)C(C)(C)C)[Si](C)(C)C(C)(C)C2178.0Standard non polar33892256
O-Acetylserine,3TBDMS,isomer #1CC(=O)OC[C@@H](C(=O)O[Si](C)(C)C(C)(C)C)N([Si](C)(C)C(C)(C)C)[Si](C)(C)C(C)(C)C2113.3Standard polar33892256
Spectra

GC-MS Spectra

Spectrum TypeDescriptionSplash KeyDeposition DateSourceView
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (2 TMS)splash10-01c0-0900000000-cbac2ae436dcca0d02512014-06-16HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (2 TMS)splash10-01c0-0900000000-7c5ef6cc55e1a01984af2014-06-16HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (2 TMS)splash10-00di-6900000000-f2863fb0291664c5ca212014-06-16HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-MS (2 TMS)splash10-00yi-0910000000-4eb5131c64279fbabbfb2014-06-16HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-EI-TOF (Non-derivatized)splash10-01c0-0900000000-cbac2ae436dcca0d02512017-09-12HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-EI-TOF (Non-derivatized)splash10-01c0-0900000000-7c5ef6cc55e1a01984af2017-09-12HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-EI-TOF (Non-derivatized)splash10-00di-6900000000-f2863fb0291664c5ca212017-09-12HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - O-Acetylserine GC-MS (Non-derivatized)splash10-00yi-0910000000-4eb5131c64279fbabbfb2017-09-12HMDB team, MONA, MassBankView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - O-Acetylserine GC-MS (Non-derivatized) - 70eV, Positivesplash10-0006-9000000000-1a24fb3faa274e72fcc52016-09-22Wishart LabView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - O-Acetylserine GC-MS (1 TMS) - 70eV, Positivesplash10-006x-9300000000-048d27b5feab5a974f8d2017-10-06Wishart LabView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - O-Acetylserine 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 - O-Acetylserine LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Positive-QTOFsplash10-052r-9700000000-798191f65808f670b0b82012-08-31HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine LC-ESI-QTOF , positive-QTOFsplash10-052r-9700000000-798191f65808f670b0b82017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine LC-ESI-QTOF 35V, negative-QTOFsplash10-0ai0-9000000000-48b5a588a0a8900448382020-07-21HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Negative-QTOFsplash10-00di-9400000000-6ea6ba6b54ea90c564162021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 10V, Negative-QTOFsplash10-05gj-9400000000-32253d09352cdfb8c3182021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Positive-QTOFsplash10-022l-9000000000-155f852f94fd442482f22021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 40V, Positive-QTOFsplash10-0006-9000000000-e88b0e868a77f604b59c2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 20V, Negative-QTOFsplash10-0089-9100000000-c7a43c74f2dde018ff1b2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Negative-QTOFsplash10-00dj-9600000000-304c64ed85255dae12e82021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 10V, Positive-QTOFsplash10-0btl-9400000000-7aa1b76f2e2dc60863112021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 20V, Positive-QTOFsplash10-01ox-9000000000-fd8ce6d36426fce8d3432021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 40V, Negative-QTOFsplash10-01bc-9000000000-abc90d9cacd4b889cd962021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Positive-QTOFsplash10-0002-2900000000-d04884f0db647a14fc8d2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Positive-QTOFsplash10-052r-8900000000-c8515198104000e957772021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Negative-QTOFsplash10-0002-4900000000-1942c426e3cf9c8b41c62021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Negative-QTOFsplash10-00di-9400000000-8d3a49712627498e2c9b2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Positive-QTOFsplash10-052r-9700000000-cf8d37dfdbdee7d766282021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Positive-QTOFsplash10-052r-9700000000-32279928e0b151d0e1da2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - O-Acetylserine 35V, Negative-QTOFsplash10-0002-6900000000-cb1c33a71a73963cf0c12021-09-20HMDB team, MONAView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - O-Acetylserine 10V, Positive-QTOFsplash10-0uea-3900000000-ef46289d46aa69d40d482016-09-12Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - O-Acetylserine 20V, Positive-QTOFsplash10-0udr-9700000000-221b830dc83fdf0795272016-09-12Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - O-Acetylserine 40V, Positive-QTOFsplash10-0006-9000000000-52a79cff992a3a467f062016-09-12Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - O-Acetylserine 10V, Negative-QTOFsplash10-0002-6900000000-4e0de865dfcc2446fe142016-09-12Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - O-Acetylserine 20V, Negative-QTOFsplash10-0a4i-9300000000-5a3f4b66b56fbaca505c2016-09-12Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - O-Acetylserine 40V, Negative-QTOFsplash10-0a4l-9000000000-123b2507eee8f6a9f0642016-09-12Wishart LabView Spectrum

NMR Spectra

Spectrum TypeDescriptionDeposition DateSourceView
Predicted 1D NMR1H NMR Spectrum (1D, 100 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 100 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 1000 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 1000 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 200 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 200 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 300 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 300 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 400 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 400 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 500 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 500 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 600 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 600 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 700 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 700 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 800 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 800 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR1H NMR Spectrum (1D, 900 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum
Predicted 1D NMR13C NMR Spectrum (1D, 900 MHz, D2O, predicted)2021-09-25Wishart LabView Spectrum

IR Spectra

Spectrum TypeDescriptionDeposition DateSourceView
Predicted IR SpectrumIR Ion Spectrum (Predicted IRIS Spectrum, Adduct: [M-H]-)2023-02-03FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Predicted IRIS Spectrum, Adduct: [M+H]+)2023-02-03FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Predicted IRIS Spectrum, Adduct: [M+Na]+)2023-02-03FELIX labView Spectrum
Biological Properties
Cellular Locations
  • Cytoplasm (predicted from logP)
Biospecimen Locations
  • Blood
  • Urine
Tissue Locations
  • Prostate
Pathways
Normal Concentrations
BiospecimenStatusValueAgeSexConditionReferenceDetails
BloodExpected but not QuantifiedNot QuantifiedNot AvailableNot Available
Normal
      Not Available
details
UrineDetected and Quantified24.7 umol/mmol creatinineAdult (>18 years old)BothNormal details
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDDB01837
Phenol Explorer Compound IDNot Available
FooDB IDFDB031064
KNApSAcK IDC00007459
Chemspider ID89874
KEGG Compound IDC00979
BioCyc IDACETYLSERINE
BiGG IDNot Available
Wikipedia LinkO-Acetylserine
METLIN ID3270
PubChem Compound99478
PDB IDNot Available
ChEBI ID17981
Food Biomarker OntologyNot Available
VMH IDACSER
MarkerDB IDNot Available
Good Scents IDNot Available
References
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
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. Sugahara K, Zhang J, Kodama H: Liquid chromatographic-mass spectrometric analysis of N-acetylamino acids in human urine. J Chromatogr B Biomed Appl. 1994 Jul 1;657(1):15-21. [PubMed:7952062 ]