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Galactose Structure: Definitions, Etymology, Formula, Properties, Applications, Sources, and Galactosemia

Nikita Parmar

Updated on 21st July, 2023 , 4 min read

Galactose Structure Overview

Lactose is created when a galactose molecule binds to a glucose molecule. Its molecular weight is 180 g/mol. Lactose, which is present in milk and dairy products, is its primary dietary source. A few fruits and vegetables contain galactose in addition to lactose. Galactosemia is a deadly condition that may be easily detected at birth but is not treatable due to recessive genetics

What is Galactose?

The monosaccharide sugar galactose, frequently abbreviated as Gal, is about 65% as sweet as sucrose and about as sweet as glucose. It is a C-4 epimer of glucose and an aldohexose. A lactose molecule is created when two molecules of galactose and glucose are joined. Galactan, a naturally occurring type of polymeric carbohydrate, is a polymeric form of galactose that may be found in hemicellulose and serves as the core of Galatians. Because it is a part of the glycoproteins (oligosaccharide-protein complexes) that are present in nerve tissue, D-galactose is sometimes referred to as brain sugar.

Galatose Strucutre

Etymology of Galactose Structure

The Greek letter o, galactose, which means "of milk," and the general chemical suffix for sugars, -ose, are the sources of the term galactose, which was first used by Charles Weissman in the middle of the 19th century. The word's origin is similar to that of lactose in that both words derive from roots that mean "milk sugar." A disaccharide comprising galactose and glucose is lactose.

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Formula for Galactose Structure

A monosaccharide sugar, galactose has a molecular mass of 180 g/mol and the chemical formula is C₆H₁₂O₆. Galactose and glucose combine to generate the disaccharide known as lactose. Both cyclic and open-chain cyclic forms of galactose are present, with the latter having a carbonyl group connected to the chain's terminus. 

Galatose Strucutre

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What is the Structure of Galactose?

Open-chain and cyclic galactose structures are two types of galactose structures. The open-chain form has a carbonyl at the end. The galactose formula can be used to help build its structure.Two of the isomers have pyranose rings with six members, whereas the other two have furanose rings with five members. The exocyclic 1,2-diol of galactofuranose, which is present in bacteria, fungi, and protozoa, is identified by the putative chordate immune lectin intelectin. The cyclic form has two anomers,alpha, and beta because the change from the open-chain to the cyclic form necessitates the development of a new stereocenter at the location of the open-chain carbonyl. In the beta form, the alcohol group is in the equatorial position, whereas in the alpha form, it is in the axial position.

Galatose Strucutre

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Properties of Galactose Structure

The following table gives details about the properties of galactose structure-

Particulars

Details

IUPAC Name 

(3R,4S,5R,6R)-6-(hydroxymethyl)oxane-2,3,4,5-tetrol

Chemical Formula of Galactose Structure

C₆H₁₂O₆

Molecular Mass of Galactose Structure

180.156 g/mol

Odour

Odourless

Density of Galactose Structure

1.5 g/cm⁻³

Appearance 

White Solid

Melting Point of Galactose Structure

168–170 ℃

Hydrogen Bond Donor Count

5

Hydrogen Bond Acceptor Count

6

Rotatable Bond Count

1

Solubility

Soluble in water but slightly soluble in ethanol 

Facts about Galactose Structure

A simple sugar called galactose is metabolized into energy by the liver. This sugar is frequently consumed by people and has a number of uses. Since galactose is a precursor to the creation of glucose, it is crucial for the generation of energy. The body's demand for galactose is satisfied through the metabolic conversion of D-glucose to D-galactose. It is an essential part of the glycolipids found in the myelin sheaths of nerve cells in the brain. It is hence also referred to as "brain sugar." 

Galatose Strucutre

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Uses of Galactose Structure

The following are some of the applications of galactose structure- 

  1. A kind of sugar called galactose is essential for the body's metabolism and the supply of energy.
  2. Galactose is a tool used by researchers to explore certain disorders. 
  3. It is crucial during the formative stages of human development. 
  4. Some common vaccinations and over-the-counter medicines have galactose as a component.
  5. Studying the management and detection of conditions including Hepatitis C, liver cancer, Wilson's disease, diabetic macular edema, and focal segmental glomerulosclerosis is beneficial.
  6. The human body uses it as a route to produce glucose as fuel. 

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Sources of Galactose Structure

Our diet's main source of galactose is lactose, which may be found in dairy products like yogurt and milk. These sources break down into glucose and galactose after digestion. Celery, cherries, honey, hamburgers with toppings, low-fat mozzarella, plums, avocados, sweetened yogurt, milk-based puddings, and kiwifruit are a few examples of foods high in galactose.

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Health Risks of Galatose Structure

The following are the health hazards of galactose structure-

  1. Galactose consumption too much might cause tooth decay.
  2. It might have minor laxative effects when taken in large doses.
  3. Some individuals may even experience negative side effects, including rashes, itching, extreme vertigo, and respiratory problems.

Galactosemia

Galactosemia is a genetic condition in which a person's body no longer has the capacity to convert galactose to glucose. As a result, the person has difficulty with carbohydrate metabolism and cannot properly digest milk and dairy products. The Galactose-1-phosphate uridinetransferase (GALT) enzyme, which is crucial for converting galactose into glucose, becomes inadequate in the body as a result of this illness. Treatment should begin as soon as possible after birth because the problem is genetically transmitted, and failing to do so might result in both intellectual handicaps and life-threatening conditions.

Frequently Asked Questions

What is galactose’s primary source?

Ans. Lactose, a disaccharide sugar that contains both galactose and glucose, is the primary source of galactose. Milk and dairy products are the principal sources of lactose (and galactose); however, traces of pure galactose can also be found in several fruits and vegetables.

What is galactose’s IUPAC name?

Ans. The name of galactose according to the IUPAC is (3R,4S,5R,6R)-6-(hydroxymethyl)oxane-2,3,4,5-tetrol

Galactose is a lower sugar, right?

Ans. Yes, Galactose is a lowering food. Since they include an aldehyde group (if they are aldoses) or may tautomerize in solution to generate an aldehyde group (if they are ketoses), all forms of monosaccharides are really reducing sugars. Galactose, glucose, glyceraldehyde, fructose, ribose, and xylose are a few common monosaccharides.

What procedure does the body go through in order to digest galactose?

Ans. This entire conversion process takes place in the mucosal membrane of the small intestine, starting with the conversion of lactose into galactose and glucose by the action of an enzyme called lactase in our stomach, followed by the phosphorylation of galactose to galactose 1-phosphate by galactokinase, and finally the final step of glycolysis that transforms the galactose into glucose. Following the transformation of galactose into glucose, the glucose is first partially digested before being absorbed by the circulation in various ways.

What happens to galactose once it has been absorbed?

Ans. The blood’s galactose and fructose are taken by the liver, where they are later changed into various metabolites. The liver absorbs the majority of fructose when it is consumed in moderation. Then it is changed into lactate, glucose, and glycogen. A part of it could also undergo oxidation or be transformed into fatty acids and uric acid.

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