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Showing NP-Card for 2-Hydroxybutyric acid (NP0000052)

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Record Information
Version1.0
Created at2005-11-16 15:48:42 UTC
Updated at2022-01-17 18:53:24 UTC
NP-MRD IDNP0000052
Secondary Accession NumbersNone
Natural Product Identification
Common Name2-Hydroxybutyric acid
Description2-Hydroxybutyric acid (alpha-hydroxybutyrate) is an organic acid derived from alpha-ketobutyrate. Alpha-Ketobutyrate is produced by amino acid catabolism (threonine and methionine) and glutathione anabolism (cysteine formation pathway) and is metabolized to propionyl-CoA and carbon dioxide (PMID: 20526369 ). 2-Hydroxybutyric acid is formed as a by-product of the formation of alpha-ketobutyrate via a reaction catalyzed by lactate dehydrogenase (LDH) or alpha-hydroxybutyrate dehydrogenase (alphaHBDH). Alpha-Hydroxybutyric acid is primarily produced in mammalian hepatic tissues that catabolize L-threonine or synthesize glutathione. Oxidative stress or detoxification of xenobiotics in the liver can dramatically increase the rate of hepatic glutathione synthesis. Under such metabolic stress conditions, supplies of L-cysteine for glutathione synthesis become limiting, so homocysteine is diverted from the transmethylation pathway (which forms methionine) into the transsulfuration pathway (which forms cystathionine). 2-Hydroxybutyrate is released as a byproduct when cystathionine is cleaved into cysteine that is incorporated into glutathione. Chronic shifts in the rate of glutathione synthesis may be reflected by urinary excretion of 2-hydroxybutyrate. 2-Hydroxybutyrate is an early marker for both insulin resistance and impaired glucose regulation that appears to arise due to increased lipid oxidation and oxidative stress (PMID: 20526369 ). 2-Hydroxybutyric acid is often found in the urine of patients suffering from lactic acidosis and ketoacidosis. 2-Hydroxybutyric acid generally appears at high concentrations in situations related to deficient energy metabolism (e.G. Birth asphyxia) and also in inherited metabolic diseases affecting the central nervous system during neonatal development, such as "cerebral" lactic acidosis, glutaric aciduria type II, dihydrolipoyl dehydrogenase (E3) deficiency, and propionic acidemia. More recently it has been noted that elevated levels of alpha-hydroxybutyrate in the plasma is a good marker for early-stage type II diabetes (PMID: 19166731 ). It was concluded from studies done in the mid-1970's that an increased NADH2/NAD ratio was the most important factor for the production of 2-hydroxybutyric acid (PMID: 168632 ).
Structure
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MOL3D MOLSDF3D SDFPDB3D PDBSMILESInChI

MOL for NP0000052 (2-Hydroxybutyric acid)


  Mrv1652303182019212D          

  7  6  0  0  0  0            999 V2000
 9998.9586 9998.7576    0.0000 C   0  0  2  0  0  0  0  0  0  0  0  0
 9998.2439 9999.1697    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
 9997.5292 9998.7576    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
 9998.2439 9999.9944    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
 9999.6740 9999.1697    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
10000.3874 9998.7576    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
 9998.9586 9997.9323    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  1  0  0  0  0
  1  5  1  0  0  0  0
  1  7  1  6  0  0  0
  2  3  1  0  0  0  0
  2  4  2  0  0  0  0
  5  6  1  0  0  0  0
M  END
Download

3D MOL for NP0000052 (2-Hydroxybutyric acid)

HMDB0000008
     RDKit          3D
2-Hydroxybutyric acid
 15 14  0  0  0  0  0  0  0  0999 V2000
   -2.0810    0.1795    0.1718 C   0  0  0  0  0  0  0  0  0  0  0  0
   -0.8784   -0.0836   -0.6959 C   0  0  0  0  0  0  0  0  0  0  0  0
    0.3603   -0.2130    0.1861 C   0  0  2  0  0  0  0  0  0  0  0  0
    0.5761    0.9543    0.9125 O   0  0  0  0  0  0  0  0  0  0  0  0
    1.5694   -0.4635   -0.6342 C   0  0  0  0  0  0  0  0  0  0  0  0
    1.5924   -1.4839   -1.3814 O   0  0  0  0  0  0  0  0  0  0  0  0
    2.6691    0.3595   -0.6233 O   0  0  0  0  0  0  0  0  0  0  0  0
   -1.8279    0.4468    1.2091 H   0  0  0  0  0  0  0  0  0  0  0  0
   -2.7275   -0.7413    0.2478 H   0  0  0  0  0  0  0  0  0  0  0  0
   -2.7336    0.9877   -0.2330 H   0  0  0  0  0  0  0  0  0  0  0  0
   -0.6935    0.7537   -1.4111 H   0  0  0  0  0  0  0  0  0  0  0  0
   -1.0170   -1.0452   -1.2245 H   0  0  0  0  0  0  0  0  0  0  0  0
    0.2225   -1.0364    0.9135 H   0  0  0  0  0  0  0  0  0  0  0  0
    1.4711    1.3559    0.7177 H   0  0  0  0  0  0  0  0  0  0  0  0
    3.4980    0.0294   -0.1567 H   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  1  0
  2  3  1  0
  3  4  1  0
  3  5  1  0
  5  6  2  0
  5  7  1  0
  1  8  1  0
  1  9  1  0
  1 10  1  0
  2 11  1  0
  2 12  1  0
  3 13  1  1
  4 14  1  0
  7 15  1  0
M  END
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3D SDF for NP0000052 (2-Hydroxybutyric acid)


  Mrv1652303182019212D          

  7  6  0  0  0  0            999 V2000
 9998.9586 9998.7576    0.0000 C   0  0  2  0  0  0  0  0  0  0  0  0
 9998.2439 9999.1697    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
 9997.5292 9998.7576    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
 9998.2439 9999.9944    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
 9999.6740 9999.1697    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
10000.3874 9998.7576    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
 9998.9586 9997.9323    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  1  0  0  0  0
  1  5  1  0  0  0  0
  1  7  1  6  0  0  0
  2  3  1  0  0  0  0
  2  4  2  0  0  0  0
  5  6  1  0  0  0  0
M  END
> <DATABASE_ID>
NP0000052

> <DATABASE_NAME>
NP-MRD

> <SMILES>
CC[C@H](O)C(O)=O

> <INCHI_IDENTIFIER>
InChI=1S/C4H8O3/c1-2-3(5)4(6)7/h3,5H,2H2,1H3,(H,6,7)/t3-/m0/s1

> <INCHI_KEY>
AFENDNXGAFYKQO-VKHMYHEASA-N

> <FORMULA>
C4H8O3

> <MOLECULAR_WEIGHT>
104.105

> <EXACT_MASS>
104.047344118

> <JCHEM_ACCEPTOR_COUNT>
3

> <JCHEM_ATOM_COUNT>
15

> <JCHEM_AVERAGE_POLARIZABILITY>
9.97578475747683

> <JCHEM_BIOAVAILABILITY>
1

> <JCHEM_DONOR_COUNT>
2

> <JCHEM_FORMAL_CHARGE>
0

> <JCHEM_GHOSE_FILTER>
0

> <JCHEM_IUPAC>
(2S)-2-hydroxybutanoic acid

> <ALOGPS_LOGP>
-0.16

> <JCHEM_LOGP>
0.050692876999999914

> <ALOGPS_LOGS>
0.67

> <JCHEM_MDDR_LIKE_RULE>
0

> <JCHEM_NUMBER_OF_RINGS>
0

> <JCHEM_PHYSIOLOGICAL_CHARGE>
-1

> <JCHEM_PKA>
14.293154365104638

> <JCHEM_PKA_STRONGEST_ACIDIC>
3.989998858113875

> <JCHEM_PKA_STRONGEST_BASIC>
-3.7935876935907205

> <JCHEM_POLAR_SURFACE_AREA>
57.53

> <JCHEM_REFRACTIVITY>
23.363799999999998

> <JCHEM_ROTATABLE_BOND_COUNT>
2

> <JCHEM_RULE_OF_FIVE>
1

> <ALOGPS_SOLUBILITY>
4.84e+02 g/l

> <JCHEM_TRADITIONAL_IUPAC>
(S)-2-hydroxybutyric acid

> <JCHEM_VEBER_RULE>
0

$$$$
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3D-SDF for NP0000052 (2-Hydroxybutyric acid)

HMDB0000008
     RDKit          3D
2-Hydroxybutyric acid
 15 14  0  0  0  0  0  0  0  0999 V2000
   -2.0810    0.1795    0.1718 C   0  0  0  0  0  0  0  0  0  0  0  0
   -0.8784   -0.0836   -0.6959 C   0  0  0  0  0  0  0  0  0  0  0  0
    0.3603   -0.2130    0.1861 C   0  0  2  0  0  0  0  0  0  0  0  0
    0.5761    0.9543    0.9125 O   0  0  0  0  0  0  0  0  0  0  0  0
    1.5694   -0.4635   -0.6342 C   0  0  0  0  0  0  0  0  0  0  0  0
    1.5924   -1.4839   -1.3814 O   0  0  0  0  0  0  0  0  0  0  0  0
    2.6691    0.3595   -0.6233 O   0  0  0  0  0  0  0  0  0  0  0  0
   -1.8279    0.4468    1.2091 H   0  0  0  0  0  0  0  0  0  0  0  0
   -2.7275   -0.7413    0.2478 H   0  0  0  0  0  0  0  0  0  0  0  0
   -2.7336    0.9877   -0.2330 H   0  0  0  0  0  0  0  0  0  0  0  0
   -0.6935    0.7537   -1.4111 H   0  0  0  0  0  0  0  0  0  0  0  0
   -1.0170   -1.0452   -1.2245 H   0  0  0  0  0  0  0  0  0  0  0  0
    0.2225   -1.0364    0.9135 H   0  0  0  0  0  0  0  0  0  0  0  0
    1.4711    1.3559    0.7177 H   0  0  0  0  0  0  0  0  0  0  0  0
    3.4980    0.0294   -0.1567 H   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  1  0
  2  3  1  0
  3  4  1  0
  3  5  1  0
  5  6  2  0
  5  7  1  0
  1  8  1  0
  1  9  1  0
  1 10  1  0
  2 11  1  0
  2 12  1  0
  3 13  1  1
  4 14  1  0
  7 15  1  0
M  END
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PDB for NP0000052 (2-Hydroxybutyric acid)

HEADER    PROTEIN                                 18-MAR-20   NONE
TITLE     NULL                                                        
COMPND    NULL                                                        
SOURCE    NULL                                                        
KEYWDS    NULL                                                        
EXPDTA    NULL                                                        
AUTHOR    Marvin                                                      
REVDAT   1   18-MAR-20         0                                  
HETATM    1  C   UNK     0    8664.7238664.348   0.000  0.00  0.00           C+0
HETATM    2  C   UNK     0    8663.3898665.117   0.000  0.00  0.00           C+0
HETATM    3  O   UNK     0    8662.0558664.348   0.000  0.00  0.00           O+0
HETATM    4  O   UNK     0    8663.3898666.656   0.000  0.00  0.00           O+0
HETATM    5  C   UNK     0    8666.0588665.117   0.000  0.00  0.00           C+0
HETATM    6  C   UNK     0    8667.3908664.348   0.000  0.00  0.00           C+0
HETATM    7  O   UNK     0    8664.7238662.807   0.000  0.00  0.00           O+0
CONECT    1    2    5    7                                                  
CONECT    2    1    3    4                                                  
CONECT    3    2                                                            
CONECT    4    2                                                            
CONECT    5    1    6                                                       
CONECT    6    5                                                            
CONECT    7    1                                                            
MASTER        0    0    0    0    0    0    0    0    7    0   12    0
END
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3D PDB for NP0000052 (2-Hydroxybutyric acid)

COMPND    HMDB0000008
HETATM    1  C1  UNL     1      -2.081   0.179   0.172  1.00  0.00           C  
HETATM    2  C2  UNL     1      -0.878  -0.084  -0.696  1.00  0.00           C  
HETATM    3  C3  UNL     1       0.360  -0.213   0.186  1.00  0.00           C  
HETATM    4  O1  UNL     1       0.576   0.954   0.913  1.00  0.00           O  
HETATM    5  C4  UNL     1       1.569  -0.463  -0.634  1.00  0.00           C  
HETATM    6  O2  UNL     1       1.592  -1.484  -1.381  1.00  0.00           O  
HETATM    7  O3  UNL     1       2.669   0.360  -0.623  1.00  0.00           O  
HETATM    8  H1  UNL     1      -1.828   0.447   1.209  1.00  0.00           H  
HETATM    9  H2  UNL     1      -2.727  -0.741   0.248  1.00  0.00           H  
HETATM   10  H3  UNL     1      -2.734   0.988  -0.233  1.00  0.00           H  
HETATM   11  H4  UNL     1      -0.693   0.754  -1.411  1.00  0.00           H  
HETATM   12  H5  UNL     1      -1.017  -1.045  -1.224  1.00  0.00           H  
HETATM   13  H6  UNL     1       0.222  -1.036   0.913  1.00  0.00           H  
HETATM   14  H7  UNL     1       1.471   1.356   0.718  1.00  0.00           H  
HETATM   15  H8  UNL     1       3.498   0.029  -0.157  1.00  0.00           H  
CONECT    1    2    8    9   10
CONECT    2    3   11   12
CONECT    3    4    5   13
CONECT    4   14
CONECT    5    6    6    7
CONECT    7   15
END
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SMILES for NP0000052 (2-Hydroxybutyric acid)

CC[C@H](O)C(O)=O
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INCHI for NP0000052 (2-Hydroxybutyric acid)

InChI=1S/C4H8O3/c1-2-3(5)4(6)7/h3,5H,2H2,1H3,(H,6,7)/t3-/m0/s1
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View in JSmol
Synonyms
ValueSource
(S)-2-Hydroxybutanoic acidChEBI
2-HydroxybutyrateChEBI
L-2-Hydroxybutanoic acidChEBI
L-2-Hydroxybutyric acidChEBI
L-alpha-Hydroxybutanoic acidChEBI
L-alpha-Hydroxybutyric acidChEBI
(S)-2-HydroxybutanoateGenerator
L-2-HydroxybutanoateGenerator
L-2-HydroxybutyrateGenerator
L-a-HydroxybutanoateGenerator
L-a-Hydroxybutanoic acidGenerator
L-alpha-HydroxybutanoateGenerator
L-Α-hydroxybutanoateGenerator
L-Α-hydroxybutanoic acidGenerator
L-a-HydroxybutyrateGenerator
L-a-Hydroxybutyric acidGenerator
L-alpha-HydroxybutyrateGenerator
L-Α-hydroxybutyrateGenerator
L-Α-hydroxybutyric acidGenerator
(S)-2-HydroxybutyrateHMDB
2-HydroxybutanoateHMDB
(+)-2-Hydroxy-N-butyric acidHMDB
(+)-2-Hydroxybutanoic acidHMDB
(+)-2-Hydroxybutyric acidHMDB
(+)-alpha-Hydroxybutyric acidHMDB
(+)-Α-hydroxybutyric acidHMDB
(2S)-2-Hydroxybutanoic acidHMDB
(S)-(+)-2-Hydroxybutanoic acidHMDB
(S)-2-Hydroxybutyric acidHMDB
2-Hydroxybutanoic acidHMDB
alpha-Hydroxy-N-butyric acidHMDB
alpha-Hydroxybutanoic acidHMDB
alpha-Hydroxybutyric acidHMDB
Α-hydroxy-N-butyric acidHMDB
Α-hydroxybutanoic acidHMDB
Α-hydroxybutyric acidHMDB
2-Hydroxybutyric acidChEBI
Chemical FormulaC4H8O3
Average Mass104.1045 Da
Monoisotopic Mass104.04734 Da
IUPAC Name(2S)-2-hydroxybutanoic acid
Traditional Name(S)-2-hydroxybutyric acid
CAS Registry Number600-15-7
SMILES
CCC(O)C(O)=O
InChI Identifier
InChI=1S/C4H8O3/c1-2-3(5)4(6)7/h3,5H,2H2,1H3,(H,6,7)
InChI KeyAFENDNXGAFYKQO-UHFFFAOYSA-N
Experimental Spectra
Spectrum TypeDescriptionDepositor EmailDepositor OrganizationDepositorDeposition DateView
1D NMR1H NMR Spectrum (1D, 700 MHz, H2O, simulated)Ahselim2022-01-17View Spectrum
1D NMR1H NMR Spectrum (1D, 700 MHz, H2O, experimental)Ahselim2022-01-17View Spectrum
1D NMR1H NMR Spectrum (1D, 600 MHz, H2O, experimental)Wishart LabWishart LabDavid Wishart2021-06-20View Spectrum
2D NMR[1H, 13C]-HSQC NMR Spectrum (2D, 600 MHz, H2O, experimental)Wishart LabWishart LabDavid Wishart2021-06-20View Spectrum
Predicted Spectra
Not Available
Chemical Shift Submissions
Not Available
Species
Species of Origin
Species NameSourceReference
Aloe africanaLOTUS Database
Anas platyrhynchosFooDB
AnatidaeFooDB
Anser anserFooDB
Bison bisonFooDB
Bos taurusFooDB
Bos taurus X Bison bisonFooDB
Bubalus bubalisFooDB
Capra aegagrus hircusFooDB
CervidaeFooDB
Cervus canadensisFooDB
Chlamydomonas reinhardtiiLOTUS Database
ColumbaFooDB
ColumbidaeFooDB
Dromaius novaehollandiaeFooDB
Equus caballusFooDB
Gallus gallusFooDB
Homo sapiensLOTUS Database
Homo sapiens (Serum)Animalia
Homo sapiens (Urine)Animalia
Lagopus mutaFooDB
LeporidaeFooDB
Lepus timidusFooDB
Melanitta fuscaFooDB
Meleagris gallopavoFooDB
Numida meleagrisFooDB
OdocoileusFooDB
OryctolagusFooDB
Ovis ariesFooDB
PhasianidaeFooDB
Phasianus colchicusFooDB
Struthio camelusFooDB
Sus scrofaFooDB
Sus scrofa domesticaFooDB
Chemical Taxonomy
Description Belongs to the class of organic compounds known as alpha hydroxy acids and derivatives. These are organic compounds containing a carboxylic acid substituted with a hydroxyl group on the adjacent carbon.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassHydroxy acids and derivatives
Sub ClassAlpha hydroxy acids and derivatives
Direct ParentAlpha hydroxy acids and derivatives
Alternative Parents
Substituents
  • Fatty acid
  • Alpha-hydroxy acid
  • Secondary alcohol
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Carboxylic acid derivative
  • Organic oxygen compound
  • Organic oxide
  • Hydrocarbon derivative
  • Organooxygen compound
  • Carbonyl group
  • Alcohol
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors
Physical Properties
StateSolid
Experimental Properties
PropertyValueReference
Melting Point44.2 °CNot Available
Boiling Point118-120 °CNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
PropertyValueSource
Water Solubility484 g/LALOGPS
logP-0.16ALOGPS
logP0.051ChemAxon
logS0.67ALOGPS
pKa (Strongest Acidic)3.99ChemAxon
pKa (Strongest Basic)-3.8ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area57.53 ŲChemAxon
Rotatable Bond Count2ChemAxon
Refractivity23.36 m³·mol⁻¹ChemAxon
Polarizability9.98 ųChemAxon
Number of Rings0ChemAxon
BioavailabilityYesChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
HMDB IDHMDB0000008
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FoodDB IDFDB021867
KNApSAcK IDC00052120
Chemspider ID389701
KEGG Compound IDC05984
BioCyc IDCPD-3564
BiGG IDNot Available
Wikipedia Link2-Hydroxybutyric_acid
METLIN IDNot Available
PubChem Compound440864
PDB IDNot Available
ChEBI ID50613
Good Scents IDNot Available
References
General References
  1. Sweatman BC, Farrant RD, Holmes E, Ghauri FY, Nicholson JK, Lindon JC: 600 MHz 1H-NMR spectroscopy of human cerebrospinal fluid: effects of sample manipulation and assignment of resonances. J Pharm Biomed Anal. 1993 Aug;11(8):651-64. [PubMed:8257730 ]
  2. Landaas S, Pettersen JE: Clinical conditions associated with urinary excretion of 2-hydroxybutyric acid. Scand J Clin Lab Invest. 1975 May;35(3):259-66. [PubMed:168632 ]
  3. 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 ]
  4. Li X, Xu Z, Lu X, Yang X, Yin P, Kong H, Yu Y, Xu G: Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for metabonomics: Biomarker discovery for diabetes mellitus. Anal Chim Acta. 2009 Feb 9;633(2):257-62. doi: 10.1016/j.aca.2008.11.058. Epub 2008 Dec 3. [PubMed:19166731 ]
  5. Gall WE, Beebe K, Lawton KA, Adam KP, Mitchell MW, Nakhle PJ, Ryals JA, Milburn MV, Nannipieri M, Camastra S, Natali A, Ferrannini E: alpha-hydroxybutyrate is an early biomarker of insulin resistance and glucose intolerance in a nondiabetic population. PLoS One. 2010 May 28;5(5):e10883. doi: 10.1371/journal.pone.0010883. [PubMed:20526369 ]
  6. Herdman MT, Sriboonvorakul N, Leopold SJ, Douthwaite S, Mohanty S, Hassan MM, Maude RJ, Kingston HW, Plewes K, Charunwatthana P, Silamut K, Woodrow CJ, Ghose A, Chotinavich K, Hossain MA, Faiz MA, Mishra S, Leepipatpiboon N, White NJ, Day NP, Tarning J, Dondorp AM: The role of previously unmeasured organic acids in the pathogenesis of severe malaria. Crit Care. 2015 Sep 7;19:317. doi: 10.1186/s13054-015-1023-5. [PubMed:26343146 ]
  7. (). Aldrich Library of FT-IR Spectra, 1st edn., 1985, 1, 548D. .
  8. (). Mori, K. et al., Tetrahedron, 1979, 35, 1601. .
  9. (). Levene, P.A. et al., J. Biol. Chem., 1941, 141, 391. .
  10. (). Duvillier, E., Ann. Chim. Phys., 1879, 17, 532. .
  11. (). Chenault, H.K. et al., J.O.C., 1987, 52, 2608. .
  12. (). Aldrich Library of 13C and 1H FT NMR Spectra, 1992, 1, 854B. .
  13. (). Horn, D.H.S. et al., J.C.S., 1954, 1460. .
  14. (). Wong, C.H. et al., J.O.C., 1985, 50, 1992. .