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Record Information
Version3.6
Creation Date2005-11-16 15:48:42 UTC
Update Date2013-05-29 19:24:57 UTC
HMDB IDHMDB00186
Secondary Accession Numbers
  • HMDB05761
Metabolite Identification
Common NameAlpha-Lactose
Descriptionalpha-Lactose is the major sugar present in milk and the main source of energy supplied to the newborn mammalian in its mother's milk. Lactose is also an important osmotic regulator of lactation. It is digested by the intestinal lactase (EC 3.2.1.108), an enzyme expressed in newborns. Its activity declines following weaning. As a result, adult mammals are normally lactose-intolerant and more than 75% of the human adult population suffers from lactase deficiency. Lactase deficiency is present in up to 80 percent of blacks and Latinos, and up to 100 percent of American Indians and Asians. Persons with lactose intolerance are unable to digest significant amounts of lactose. Common symptoms include abdominal pain and bloating, excessive flatus, and watery stool following the ingestion of foods containing lactose. A sizable number of adults believe they are lactose intolerant but do not actually have impaired lactose digestion, and some persons with lactase deficiency can tolerate moderate amounts of ingested lactose. A diagnosis of lactose intolerance can usually be made with a careful history supported by dietary manipulation. If necessary, diagnosis can be confirmed by using a breath hydrogen or lactose tolerance test. These mostly uncomfortable symptoms of lactose maldigestion are blamed for a variably dairy consumption. There is, however, emerging evidence that certain lactic acid-producing bacteria, which selectively consume prebiotics, may be beneficial against some lower intestinal diseases. Lactose maldigestion and lactose should perhaps be re-evaluated as a potential provider of such a prebiotic. Treatment consists primarily of avoiding lactose-containing foods. Lactase enzyme supplements may be helpful. The degree of lactose malabsorption varies greatly among patients with lactose intolerance, but most of them can ingest up to 350 mL of milk daily without symptoms. Lactose-intolerant patients must ensure adequate calcium intake. (PMID: 13130292 , 12216958 , 12197838 , 12018807 ).
Structure
Thumb
Synonyms
  1. (+)-lactose
  2. 1-beta-D-Galactopyranosyl-4-alpha-D-glucopyranose
  3. 1-beta-delta-Galactopyranosyl-4-alpha-delta-glucopyranose
  4. 4-O-Hexopyranosylhexose
  5. a-Lactose
  6. Aletobiose
  7. alpha-Lactose
  8. Anhydrous lactose
  9. Dilactose
  10. Fast-Flo Lactose
  11. Flowlac 100
  12. Galactinum
  13. Glc-(4-1)Gal
  14. Granulac 140M
  15. Lactin
  16. Lactin (carbohydrate)
  17. Lactobiose
  18. Lactohale 300
  19. Lactose
  20. Lactose anhydride
  21. Lactose Fast-flo
  22. Milk sugar
  23. Osmolactan
  24. Pharmatosa DCL 21
  25. Pharmatose 21
  26. Pharmatose 325M
  27. Pharmatose DCL 15
  28. Prismalac
  29. Respitose ML 003
  30. Respitose SV 003
  31. Saccharum lactin
  32. Sachelac
  33. Sorbalac 400
  34. Sorbolac 400
  35. Spherolac
  36. Super-Tab
  37. Tablettose
  38. Tablettose 70
  39. Tablettose 80
  40. Zeparox EP
Chemical FormulaC12H22O11
Average Molecular Weight342.2965
Monoisotopic Molecular Weight342.116211546
IUPAC Name(2R,3R,4S,5R,6S)-2-(hydroxymethyl)-6-{[(2R,3S,4R,5R,6S)-4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxy}oxane-3,4,5-triol
Traditional IUPAC Nameα-lactose
CAS Registry Number63-42-3
SMILES
OC[C@H]1O[C@@H](O[C@H]2[C@H](O)[C@@H](O)[C@@H](O)O[C@@H]2CO)[C@H](O)[C@@H](O)[C@H]1O
InChI Identifier
InChI=1S/C12H22O11/c13-1-3-5(15)6(16)9(19)12(22-3)23-10-4(2-14)21-11(20)8(18)7(10)17/h3-20H,1-2H2/t3-,4-,5+,6+,7-,8-,9-,10-,11+,12+/m1/s1
InChI KeyGUBGYTABKSRVRQ-XLOQQCSPSA-N
Chemical Taxonomy
KingdomOrganic Compounds
Super ClassCarbohydrates and Carbohydrate Conjugates
ClassDisaccharides
Sub ClassDihexoses
Other Descriptors
  • Aliphatic Heteropolycyclic Compounds
  • lactose(ChEBI)
Substituents
  • 1,2 Diol
  • Acetal
  • Glycosyl Compound
  • Hemiacetal
  • O Glycosyl Compound
  • Oxane
  • Primary Alcohol
  • Secondary Alcohol
Direct ParentDihexoses
Ontology
StatusDetected and Quantified
Origin
  • Endogenous
Biofunction
  • Component of Galactose metabolism
  • Component of Glycerolipid metabolism
  • Component of Glycosphingolipid metabolism
  • Component of Keratan sulfate biosynthesis
  • Component of N-Glycan biosynthesis
ApplicationNot Available
Cellular locations
  • Cytoplasm
  • Extracellular
  • Lysosome
  • Golgi apparatus
Physical Properties
StateSolid
Experimental Properties
PropertyValueReference
Melting Point201 - 202 °CNot Available
Boiling PointNot AvailableNot Available
Water Solubility195 mg/mL at 20 °CNot Available
LogPNot AvailableNot Available
Predicted Properties
PropertyValueSource
Water Solubility586 g/LALOGPS
logP-3ALOGPS
logP-4.7ChemAxon
logS0.23ALOGPS
pKa (Strongest Acidic)11.25ChemAxon
pKa (Strongest Basic)-3ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count11ChemAxon
Hydrogen Donor Count8ChemAxon
Polar Surface Area189.53ChemAxon
Rotatable Bond Count4ChemAxon
Refractivity68.34ChemAxon
Polarizability30.96ChemAxon
Spectra
SpectraGC-MSMS/MS1D NMR2D NMR
Biological Properties
Cellular Locations
  • Cytoplasm
  • Extracellular
  • Lysosome
  • Golgi apparatus
Biofluid Locations
  • Blood
  • Urine
Tissue Location
  • Bladder
  • Gut
  • Intestine
  • Muscle
  • Platelet
  • Skin
  • Spleen
Pathways
NameSMPDB LinkKEGG Link
Galactose MetabolismSMP00043map00052
Lactose DegradationSMP00457Not Available
Lactose SynthesisSMP00444Not Available
Normal Concentrations
BiofluidStatusValueAgeSexConditionReferenceDetails
BloodExpected but not QuantifiedNot ApplicableNot AvailableNot Available
Normal
  • Not Applicable
details
UrineDetected and Quantified11.8 (1.0-24.2) umol/mmol creatinineAdult (>18 years old)Both
Normal
details
UrineDetected and Quantified30.0 (13.0-49.0) umol/mmol creatinineInfant (0-1 year old)BothNormal
    • Geigy Scientific ...
details
UrineDetected and Quantified1.45 (0.63-3.45) umol/mmol creatinineAdult (>18 years old)BothNormal
    • Geigy Scientific ...
details
UrineDetected and Quantified36.31 +/- 6.60 umol/mmol creatinineAdult (>18 years old)Not Specified
Normal
details
UrineDetected and Quantified66.02 +/- 6.60 umol/mmol creatinineAdult (>18 years old)Not Specified
Normal
details
UrineDetected and Quantified676.75 +/- 85.83 umol/mmol creatinineNewborn (0-30 days old)Not Specified
Normal
details
UrineDetected and Quantified6.08 +/- 6.07 umol/mmol creatinineInfant (0-1 year old)BothNormal details
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDDB04465
DrugBank Metabolite IDNot Available
Phenol Explorer Compound IDNot Available
Phenol Explorer Metabolite IDNot Available
FoodDB IDFDB001145
KNApSAcK IDC00001136
Chemspider ID76293
KEGG Compound IDC00243
BioCyc IDLACTOSE
BiGG ID34366
Wikipedia LinkLactose
NuGOwiki LinkHMDB00186
Metagene LinkHMDB00186
METLIN ID267
PubChem Compound84571
PDB IDLBT
ChEBI ID36219
References
Synthesis ReferenceRuffing, Anne; Mao, Zichao; Ruizhen Chen, Rachel. Metabolic engineering of Agrobacterium sp. for UDP-galactose regeneration and oligosaccharide synthesis. Metabolic Engineering (2006), 8(5), 465-473.
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Jung SK, Fujimoto D: A novel beta-galactoside-binding lectin in adult rat kidney. J Biochem (Tokyo). 1994 Sep;116(3):547-53. Pubmed: 7852273
  2. Oozeer R, Furet JP, Goupil-Feuillerat N, Anba J, Mengaud J, Corthier G: Differential activities of four Lactobacillus casei promoters during bacterial transit through the gastrointestinal tracts of human-microbiota-associated mice. Appl Environ Microbiol. 2005 Mar;71(3):1356-63. Pubmed: 15746338
  3. Dimopoulos MA, Anagnostopoulos A: Thalidomide in relapsed/refractory multiple myeloma: pivotal trials conducted outside the United States. Semin Hematol. 2003 Oct;40(4 Suppl 4):8-16. Pubmed: 15015891
  4. Muthusamy A, Erickson DR, Sheykhnazari M, Bhavanandan VP: Enhanced binding of modified pentosan polysulfate and heparin to bladder--a strategy for improved treatment of interstitial cystitis. Urology. 2006 Jan;67(1):209-13. Pubmed: 16413377
  5. Johnson JD, Simoons FJ, Hurwitz R, Grange A, Mitchell CH, Sinatra FR, Sunshine P, Robertson WV, Bennett PH, Kretchmer N: Lactose malabsorption among the Pima indians of Arizona. Gastroenterology. 1977 Dec;73(6):1299-304. Pubmed: 578795
  6. Lustenberger RW: [A 23-year old patient with chronic diarrhea. Celiac disease and lactose intolerance] Schweiz Rundsch Med Prax. 2005 Feb 2;94(5):163-4. Pubmed: 15745382
  7. Sharma A, DiCioccio RA, Allen HJ: Identification and synthesis of a novel 15 kDa beta-galactoside-binding lectin in human leukocytes. Glycobiology. 1992 Aug;2(4):285-92. Pubmed: 1421750
  8. Rana SV, Bhasin DK, Vinayak VK: Lactose hydrogen breath test in Giardia lamblia-positive patients. Dig Dis Sci. 2005 Feb;50(2):259-61. Pubmed: 15745082
  9. Mitchell JD, Brand J, Halbisch J: Weight-gain inhibition by lactose in Australian Aboriginal children. A controlled trial of normal and lactose hydrolysed milk. Lancet. 1977 Mar 5;1(8010):500-2. Pubmed: 65606
  10. Soupene E, van Heeswijk WC, Plumbridge J, Stewart V, Bertenthal D, Lee H, Prasad G, Paliy O, Charernnoppakul P, Kustu S: Physiological studies of Escherichia coli strain MG1655: growth defects and apparent cross-regulation of gene expression. J Bacteriol. 2003 Sep;185(18):5611-26. Pubmed: 12949114
  11. Yeoh E, Horowitz M, Russo A, Muecke T, Robb T, Chatterton B: The effects of abdominal irradiation for seminoma of the testis on gastrointestinal function. J Gastroenterol Hepatol. 1995 Mar-Apr;10(2):125-30. Pubmed: 7787155
  12. Bondesson E, Bengtsson T, Borgstrom L, Nilsson LE, Norrgren K, Olsson B, Svensson M, Wollmer P: Dose delivery late in the breath can increase dry powder aerosol penetration into the lungs. J Aerosol Med. 2005 Spring;18(1):23-33. Pubmed: 15741771
  13. Roberson CM: Lactose intolerance. Ala Nurse. 2004 Dec-2005 Feb;31(4):23-4; quiz 24. Pubmed: 15662762
  14. Kim KI, Lee WS, Benevenga NJ: Feeding diets containing high levels of milk products or cellulose decrease urease activity and ammonia production in rat intestine. J Nutr. 1998 Jul;128(7):1186-91. Pubmed: 9649604
  15. Gunther S, Patterson RE, Kristal AR, Stratton KL, White E: Demographic and health-related correlates of herbal and specialty supplement use. J Am Diet Assoc. 2004 Jan;104(1):27-34. Pubmed: 14702580
  16. Delaveau P: [Milk lactose. Hypothesis on its biological importance]. Ann Pharm Fr. 2003;61(5):340-2. Pubmed: 13130292
  17. Vilotte JL: Lowering the milk lactose content in vivo: potential interests, strategies and physiological consequences. Reprod Nutr Dev. 2002 Mar-Apr;42(2):127-32. Pubmed: 12216958
  18. Szilagyi A: Review article: lactose--a potential prebiotic. Aliment Pharmacol Ther. 2002 Sep;16(9):1591-602. Pubmed: 12197838
  19. Swagerty DL Jr, Walling AD, Klein RM: Lactose intolerance. Am Fam Physician. 2002 May 1;65(9):1845-50. Pubmed: 12018807

Enzymes

General function:
Involved in hydrolase activity, hydrolyzing O-glycosyl compounds
Specific function:
LPH splits lactose in the small intestine.
Gene Name:
LCT
Uniprot ID:
P09848
Molecular weight:
218584.77
General function:
Involved in transferase activity, transferring glycosyl groups
Specific function:
Responsible for the synthesis of complex-type N-linked oligosaccharides in many glycoproteins as well as the carbohydrate moieties of glycolipids. Can produce lactose.
Gene Name:
B4GALT2
Uniprot ID:
O60909
Molecular weight:
41971.815
General function:
Involved in lactose synthase activity
Specific function:
Regulatory subunit of lactose synthase, changes the substrate specificity of galactosyltransferase in the mammary gland making glucose a good acceptor substrate for this enzyme. This enables LS to synthesize lactose, the major carbohydrate component of milk. In other tissues, galactosyltransferase transfers galactose onto the N-acetylglucosamine of the oligosaccharide chains in glycoproteins.
Gene Name:
LALBA
Uniprot ID:
P00709
Molecular weight:
Not Available
General function:
Involved in transferase activity, transferring glycosyl groups
Specific function:
The Golgi complex form catalyzes the production of lactose in the lactating mammary gland and could also be responsible for the synthesis of complex-type N-linked oligosaccharides in many glycoproteins as well as the carbohydrate moieties of glycolipids. The cell surface form functions as a recognition molecule during a variety of cell to cell and cell to matrix interactions, as those occurring during development and egg fertilization, by binding to specific oligosaccharide ligands on opposing cells or in the extracellular matrix.
Gene Name:
B4GALT1
Uniprot ID:
P15291
Molecular weight:
43919.895
General function:
Involved in hydrolase activity, hydrolyzing O-glycosyl compounds
Specific function:
Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans. Isoform 2 has no beta-galactosidase catalytic activity, but plays functional roles in the formation of extracellular elastic fibers (elastogenesis) and in the development of connective tissue. Seems to be identical to the elastin-binding protein (EBP), a major component of the non-integrin cell surface receptor expressed on fibroblasts, smooth muscle cells, chondroblasts, leukocytes, and certain cancer cell types. In elastin producing cells, associates with tropoelastin intracellularly and functions as a recycling molecular chaperone which facilitates the secretions of tropoelastin and its assembly into elastic fibers.
Gene Name:
GLB1
Uniprot ID:
P16278
Molecular weight:
Not Available
General function:
Involved in glycolipid transporter activity
Specific function:
Accelerates the intermembrane transfer of various glycolipids. Catalyzes the transfer of various glycosphingolipids between membranes but does not catalyze the transfer of phospholipids. May be involved in the intracellular translocation of glucosylceramides
Gene Name:
GLTP
Uniprot ID:
Q9NZD2
Molecular weight:
23849.6
References
  1. Overington JP, Al-Lazikani B, Hopkins AL: How many drug targets are there? Nat Rev Drug Discov. 2006 Dec;5(12):993-6. Pubmed: 17139284
  2. Imming P, Sinning C, Meyer A: Drugs, their targets and the nature and number of drug targets. Nat Rev Drug Discov. 2006 Oct;5(10):821-34. Pubmed: 17016423