Galactose is a kind of monosaccharide, and its molecular formula is CsixHtwelveOsix, can be found in milk products or beets.Galactose is a compound composed of six carbons and onealdehydeConstituentmonosaccharide, classified asaldoseandHexose, is someglycoproteinAn important component of.
Galactose is a component of lactose in mammalian milk. It has been found from snails, frog eggs and bovine lungsD-galactoseConstituentPolysaccharide。It often exists in the brain and nervous tissue in the form of D-galactoside.
Galactose, yesmonosaccharideIt can be found in milk products or beets.Galactose is a monosaccharide composed of six carbons and one aldehyde group, which is classified asaldoseandHexose。Galactose is a component of lactose in mammalian milk. It has been found from snails, frog eggs and bovine lungsD-galactoseComposed of polysaccharides.It often exists in the brain and nervous tissue in the form of D-galactoside, and is alsoglycoproteinGalactose is an important component of lactose, which is absorbed fastest in the intestine.
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Galactose is often present in various plant gums in the form of polysaccharide in the plant kingdom. For example, K-carrageenan in red algae is a polysaccharide composed of D-galactose and 3,6-diethyl-D-galactose.Free galactose is present in ivy berries.Galactose is white crystal.D-galactose and L-galactose are naturally present.D-galactose generally exists in milk as the structural part of lactose. The lactose in milk is decomposed into glucose and galactose by the human body and is absorbed and utilized.
Because it contains calories, it can also be used as a nutritional sweetener.Galactose is part of the lactose molecule and the other half is glucose.stayβ-Under the catalysis of lactase, galactose can be obtained from the hydrolysis of lactose.Bifidobacterium ferments lactose to produce galactose, which is a component of cerebrosides in the brain nervous system, and is closely related to the rapid growth of the brain after birth.
D-galactose in red algae[3]Polysaccharides composed of 3,6-lacto-D-galactose, which also exist in a variety of oligosaccharides, such asMelibiose、RaffinoseEtc.Galactose in sugar beets is often associated withinositolThe galactose in some algae is combined with glycerol.Free galactose is found in ivy berries.
The galactose in food mainly comes from the lactose contained in milk.Lactose in milk provides 20% of the energy needed by lactating infants.Under normal circumstances, lactose is hydrolyzed into galactose and glucose is absorbed by the intestinal mucosa after entering the intestine.After being absorbed, galactose successively passes throughGalactokinase(GALK), galactose-l-phosphate uridyltransferase (GALT) and uridine diphosphate galactose epiisomerase (EPIM), and finally produce glucose L-phosphate into the glucose metabolism pathway.The human liver has a strong ability to convert galactose into glucose, and 50% of the galactose in human blood is converted within half an hour.
Preparation method
The simplest method to prepare galactose is the hydrolysis of lactose to obtain equivalentD-galactoseandD-glucoseD - glucose is removed by fermentation to obtain pure D - galactose with high yield.Galactose can also be obtained fromD-Lyxose It is prepared by growing carbon chain through chemical synthesis.
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Galactosemia
GalactosemiaIt is a genetic disease with abnormal galactose metabolism due toGalactose-1-phosphateUridineTransacyltransferase deficiency makes galactose 1-phosphate andGalactolAccording to the changes of erythrocyte and liver enzymes, the enzyme has several variants.Liver, kidney, eye lens and brain tissue are the main affected organs.
Galactose intolerance
Before drinking milk, check whether you are lactose tolerant, and then choose different types of dairy products. The inspection methods are divided into three categories.
1. Clinical diagnosis: the doctor determines whether the patient is tolerant to lactose according to symptoms such as abdominal pain, abdominal distention and diarrhea.The disadvantage of this method is that it cannot find the recessive lactose intolerant.
2. "Hydrogen breath test" shall be conducted after drinking milk.This practice requires special equipment. If the subject has a history of smoking or sucrose intolerance, the test results will be inaccurate.
3. After drinking milk, test the concentration of galactose in urine, which is the most commonly used method abroad at present. It is more simple, economical and reliable.
resistα-Galactose
In 1984, Galile found that anti e-galactosyl antibody (anti Gal) is the most abundant natural antibody in human body, accounting for aboutimmunoglobulin1% of the total amount can react specifically with the mammalian carbohydrate epitope Galel-3Galpl-4GlcNAc-R (i.e. galactosyl).In the next three years, it was further proved that anti Gal is a specific antibody that mediates phagocytosis of aging red blood cells by phagocytes, mainly IgG.From 1987 to 1991, in the study of Graves disease, scleroderma, Henoch Schonlein purpura, Chagas disease, malaria and other diseases, it was found that the anti Gal titer was increased, which means that the antibody may be involved in the pathogenesis of these diseases;Moreover, anti Gal unique distribution mode andα-The study of galactosyl epitopes has further deepened the understanding that anti Gal plays a leading role in xenograft rejection between humans and primates.
