Galactose, in blood

Other examples of amperometric enzyme electrodes based on the measurement of oxygen or hydrogen peroxide include electrodes for the measurement of galactose in blood (galactose oxidase,enzyme), oxalate in urine (oxalate oxidase), and cholesterol in blood serum (cholesterol oxidase). Ethanol is determined by reacting with a cofactor, nicotinamide adenine dinucleotide (NAD" ) in the presence of the enzyme alcohol dehydrogenase to produce the reduced form of NAD", NADH, which is electrochemically oxidized. Lactate in blood is similarly determined (lactate dehydrogenase enzyme). 

Galactosemia Hepatic and erythrocyte epimerase Galactose in blood and urine Hepatomegaly, jaundice, vomiting Restrict galactose calcium and vitamin D supplementation None... 

Galactose in blood and urine renal Fanconi syndrome... 

Administration of galactose during hypoglycemia Induces an Increase in blood glucose... 

An important source of galactose in the diet is the disaccharide lactose present in milk. Lactose is hydrolyzed to galactose and glucose by lactase associated with the brush border membrane of the small intestine. Along with other monosaccharides, galactose reaches the liver through the portal blood. 

In a person with glucose 6-phosphatase deficiency, ingestion of galactose or fructose causes no increase in blood glucose, nor does administration of glucagon or epinephrine. 

Defects in any of the three enzymes in this pathway cause galactosemia in humans. In galactoldnase-deficiency galactosemia, high galactose concentrations are found in blood and urine. Infants develop cataracts, caused by deposition of the galactose metabolite galac-titol in the lens. 

As to other organic substances in this context, special mention must be made of glycoproteins, which prevent blood from freezing in Arctic and Antarctic fish (De Vries, 1970 Hochachka and Somero, 1973). Glycoprotein, composed of repeated subunits of alanine and threonine bound to a disaccharide derivative of galactose, is an antifreeze agent (DeVries, 1971 Shier et al., 1972). It impedes crystal formation in blood and lowers the freezing point to -1.8°C, the lowest... 

Case B (c) Galactose 1-phosphate uridylyltransferase is an enzyme involved in conversion of galactose to glucose, which then can enter glycolysis. Absence of this enzyme leads to accumulation of galactose in the blood and excretion in the urine. A patient with this deficiency should be on a low-lactose diet (treatment 3). 

Diagnosis may be confirmed by the absence of glucose 6-phosphatase on liver biopsy. The liver cells are full of glycogen and fat. Also, the normal elevation in blood glucose from infusion of glucagon, epinephrine or galactose is absent. 

The carbohydrate end groups in various blood group mucopolysaccharides, as described by Morgan (M50), are as follows acetylgalactosamine, acetylglucosamine, and galactose on blood group substance A ... 

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