Lactose Identifiers Properties
CAS number 63-42-3
PubChem 6134
MeSH Lactose
molecule formula C12H22O11
Molar mass 342.296
except where noted otherwise, data are given for materials in their standard state(at 25°C, 100kPa)Infobox disclaimer and also references

Lactose (also described as milk sugar) is a sugar which is uncovered most especially in milk. Lactose renders up roughly 2–8% of the solids in milk. The name comes from the Latin word because that milk, add to the -ose finishing used to name sugars.




1 Chemistry



Lactose is a disaccharide that is composed of β-D-galactose and also D-glucose molecule bonded through a β1-4 glycosidic linkage.

You are watching: Why is lactose soluble in water


Lactose has a solubility that 1 in 4.63 measure %w/v. This equates to 0.216g of lactose dissolving readily in 1mL that water.

The solubility that lactose in water is 18.9049g in ~ 25°C, 25.1484g at 40°C and 37.2149g in ~ 60°C per 100g solution. That solubility in ethanol is 0.0111g in ~ 40°C and also 0.0270g in ~ 60°C every 100g solution.<1>

cradle of lactose

Infant mammals are fed on milk by their mothers. Come digest it an enzyme dubbed lactase (β-D-galactosidase) is secreted by the minister villi, and also this enzyme cleaves the molecule into its two subunits glucose and galactose for absorption.

Since lactose occurs mainly in milk, in most mammals the production of lactase gradually decreases through maturity. However, production never ceases completely; the is controlled by the presence of lactose in the diet, which subsequently deactivates the repressor that the lac operon, permitting lactase to it is in synthesized. In other words, lactose induces the synthesis of the enzyme which breaks it down.<2> (See also: gene expression.)

Many world with genealogy in Europe, the center East, India, or components of east Africa, keep normal lactase production into adulthood. In plenty of of these societies mammals such as cattle, goats, and also sheep room milked because that food. Hence, it was in these areas that gene for lifelong lactase production very first evolved.

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General: Geometry: Small/Large: Trioses: Tetroses: Pentoses: Hexoses: Disaccharides: Polymers: Glycosaminoglycans: Aminoglycosides:
Aldose | Ketose | Pyranose | Furanose
Triose | Tetrose | Pentose | Hexose | Heptose | Cyclohexane construction | Anomer | Mutarotation
Glyceraldehyde | Dihydroxyacetone | Erythrose | Threose | Erythrulose | Sedoheptulose
ketotriose | Aldotriose
Erythrulose | Erythrose | Threose
Arabinose | Deoxyribose | Lyxose | Ribose | Ribulose | Xylose | Xylulose
Glucose | Galactose | Mannose | Gulose | Idose | Talose | Allose | Altrose | fructose | Sorbose | Tagatose | Psicose | Fucose | Rhamnose
Sucrose | Lactose | Trehalose | Maltose
Glycogen | starch (Amylose | Amylopectin) | Cellulose | Chitin | Stachyose | Inulin | Dextrin
Heparin | Chondroitin sulfate | Hyaluronan | Heparan sulfate | Dermatan sulfate | Keratan sulfate
Kanamycin | Streptomycin | Tobramycin | Neomycin | Paromomycin | Apramycin | Gentamicin | Netilmicin | Amikacin

This write-up is licensed under the GNU free Documentation License. It uses product from the Wikipedia write-up "Lactose". A perform of writer is obtainable in Wikipedia.


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