The Galactose is a simple sugar or monosaccharide of six carbon atoms or hexose, which is converted to glucose in the liver as energy intake, is part of the glycolipids and glycoproteins of cell membranes of cells especially neurons.
Summary
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- 1 Description
- 2 Physical properties
- 3 Classification
- 4 Obtaining
- 5 Uses
- 1 Brain and galactose
- 6 Galactosemia
- 1 Treatment
- 7 External links
- 8 Sources
Description
Monosaccharide of the hexose family present in legumes, pectins, agar and many other foods. It is one of the components of lactose. It is a stereoisomer (epimer at position 4) of glucose . The alteration of its metabolism gives rise to diseases known as galactosemias.
Physical properties
- Density 1732 kg / m3; 1,732 g / cm3
- Molar mass 180.08 g / mol
- Melting point 440.15 K (167 ° C)
- Boiling point 683.95 K (410.8 ° C)
Classification
From the chemical point of view it is an aldose, that is, its functional chemical group is an aldehyde (CHO) located at carbon 1, or anomeric carbon . On the other hand, like glucose, it belongs to the group of hexoses, which are monosaccharides (simple carbohydrates) formed by a chain of six carbon atoms. Its molecular or empirical formula is equal to that of glucose: C 6 H 12 O 6 , although it differs from it in that it is an epimer of glucose in Carbon number 4, that is, that the alcohol group of this carbon is directed to the left (in the linear formula, in the cyclical form it is directed upwards). In its cyclical form it will be called galactopyranose, the β form existing if the– OH attached to the anomeric carbon is up, and the α-form if the -OH attached to the anomeric carbon is down. Similarly, there is the D and the L forms, the former being the most abundant naturally.
Obtaining
Galactose is synthesized by the mammary glands to produce lactose, which is a disaccharide formed by the union of glucose and galactose, therefore the greatest contribution of galactose in nutrition comes from the intake of milk lactose.
It is a monosaccharide that is obtained in the intestine, through the action of the enzyme lactase, by acting on lactose (which is the sugar in milk), in this reaction appear: glucose and galactose. Therefore, this compound is obtained from the diet (Route 19 and 18).
Applications
Brain and galactose
The galactose necessary for the activity of brain cells, especially for cerebrosides. For its part, ceramide is linked through the -OH group of sphingosine to a monosaccharide through a b-glycosidic bond. If the monosaccharide is galactose, we will have the structure called cerebroside.
Galactosemia
Galactosemia is a hereditary metabolic abnormality that is characterized by the accumulation of the disaccharide galactose in the blood and tissues, by the absence of the enzyme necessary for the galactose to transform into glucose, which will cause pathological changes.
This table includes two different disorders, on the one hand, deficiency of galactose phosphorylating enzyme (classical galactosemia) and, on the other hand, deficiency of the enzyme galactokinase.
These enzymopathies are inherited with an autosomal recessive character and in both, galactose is metabolized in the lens to galactitol, a substance that will give rise to cataracts. In classic galactosemia, in addition, galactose-1-phosphate accumulates in the tissues, causing cirrhosis, mental retardation and decreased intestinal absorption of amino acids, which in turn will also cause other disorders.
The newborn rejects milk and vomits, developing malnutrition and stunting. Signs of liver disease (hepatomegaly, jaundice) may appear, cataracts form in weeks or months, and psychomotor retardation is seen after 6-12 months. It is diagnosed by detection of galactose in urine (galactosuria) and by enzymatic analysis of red blood cells.
Treatment
Treatment consists of removing galactose-containing products, especially milk , from the diet
