galactose


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Related to galactose: saccharose

galactose:

see lactoselactose
or milk sugar,
white crystalline disaccharide (see carbohydrate). It has the same empirical formula (C12H22O11) as sucrose (cane sugar) and maltose but differs from both in structure (see isomer).
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Galactose

A monosaccharide and a constituent of oligosaccharides, notably lactose, melibiose, raffinose, and stachyose. It is also known as d -galactose and cerebrose (see illustration). Agar, gum arabic, mesquite gum, larch arabo galactan, and a variety of other gums and mucilages contain d -galactose. See Agar, Monosaccharide

Structural formula for α - d -galactoseenlarge picture
Structural formula for α - d -galactose

l -Galactose (enantiomorph of d -galactose) occurs in several polysaccharides, including agar, flaxseed mucilage, snail galactogen, and chagual gum. Since d -galactose is usually also present, hydrolysis of these polysaccharides produces dl -galactose. See Carbohydrate

Galactose

 

a monosaccharide; one of the most frequently encountered natural hexahydric alcohols, a hexose. It differs from glucose in the spatial position of the groups around the fourth carbon atom. Galactose is readily soluble in water and only slightly soluble in alcohol. It exists in aliphatic and cyclic (pyranose, or furanose) forms, which are in a state of tautomeric equilibrium:

In plant tissues galactose is a component of raffinose, melibiose, and stachyose, as well as polysaccharides — galactans, pectins, saponins, various gums and mucilages, gum arabic, and so on. In the animal and human body galactose is a component of lactose (milk sugar), galactogen, group-specific polysaccharides, cerebrosides, and muco-proteins. Galactose is part of many bacterial polysaccharides and can be fermented by so-called lactose yeast. In animal and plant tissues, galactose readily changes to glucose, which is more assimilated and can be converted to ascorbic and galacturonic acids.

L. L. KHACHATRIAN

galactose

[gə′lak‚tōs]
(biochemistry)
C6H12O6 A monosaccharide occurring in both levo and dextro forms as a constituent of plant and animal oligosaccharides (lactose and raffinose) and polysaccharides (agar and pectin). Also known as cerebrose.
References in periodicals archive ?
For fermentation assays, single colonies of the [Sc.sub.Gal] strain were inoculated in 100 mL of two different growth broths: i) BGlu: 40 g [L.sup.-1] glucose, 10 g [L.sup.-1] peptone, pH 3.5 and ii) BGal: 40 g [L.sup.-1] galactose, 10 g [L.sup.-1] peptone, pH 3.5.
Einsele (1991).Growth and metabolism of human tumor kidney cells on galactose and glucose.Cytotechnology, vol.
As shown in Figures 3(a) and 3(b), normal lenses had always been at grade 0 and isolated lenses were transparent in the whole duration, but lens opacification of galactose group gradually increased by almost one grade every 3 days.
They have suggested that the randomly occurring mutation due to an exposure to some viral or bacterial antigens enhances the binding of IgG1 with galactose deficient IgA1 molecules.
Child A2, who has a classic homozygosis mutation (Q188R/Q188R), was unable to metabolize the ingested galactose, which was confirmed by the fact that the total carbon recovered from the ingested galactose at 120 min was lower than the baseline value, with a consequent negative final result.
Disruption of neuronal-glial-vascular units in the hippocampus of ovariectomized mice injected with D- galactose. Neuroscience, 169: 596-608.
Glucose, maltose, ribose, and galactose supplementation showed the highest production of rifamycin B at 5.78, 4.89, 4.35, and 3.87 g/kgds dry sunflower oil cake at the day eight of incubation.
Measurement of Galactose. Blood for each galactose test was withdrawn 60 minutes after galactose infusion; blood samples were obtained by venipuncture 60 min after injection.
As shown in Figure 4, the complete digestion of lactose occurs within the small intestine, as neutral lactase immediately releases its glucose and galactose components for rapid absorption.
While physiological levels of plasma galactose (usually <0.5 mmol/l) do not affect the meter's readings, galactose, at the clinically relevant concentrations found in galactosaemia, is able to cause positive interference.
Chemically, guar gum is very similar to starch but instead of being composed of chains of glucose units it is made up of a backbone of mannose with some side-branches of galactose. Mannose and galactose, like glucose, are simple sugars that the body is accustomed to handling.