|
Galactose 1-phosphate
D-Galactose-1-phosphate is an intermediate in the intraconversion of glucose and uridine diphosphate galactose. It is formed from galactose by galactokinase.The improper metabolism of galactose-1-phosphate is a characteristic of galactosemia. The Leloir pathway is responsible for such metabolism of galactose and its intermediate, galactose-1-phosphate. Deficiency of enzymes found in this pathway can result in galactosemia; therefore, diagnosis of this genetic disorder occasionally involves measuring the concentration of these enzymes. One of such enzymes is galactose-1-phosphate uridylytransferase (GALT). The enzyme catalyzes the transfer of a UDP-activator group from UDP-glucose to galactose-1-phosphate. Although the cause of enzyme deficiency in the Leloir pathway is still disputed amongst researchers, some studies suggest that protein misfolding of GALT, which may lead to an unfavorable conformational change that impacts its thermal stability and substrate-binding affinity, may pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight, where it is used to make cellulose in cell walls, the most abundant carbohydrate in the world. In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as starch and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form of glucose is -glucose, while -glucose is produced synthetically in comparatively small amounts and is less biologically active. Glucose is a monosaccharide containing six carbon atoms and an aldehyde group, and is therefore an aldohexose. The glucose molecule can exist in an open-chain (acyclic) as well as ring (cyclic) form. Gluco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uridine Diphosphate Galactose
Uridine diphosphate galactose ( UDP-galactose) is an intermediate in the production of polysaccharides. It is important in nucleotide sugars metabolism, and is the substrate for the transferase B4GALT5. See also * Galactose * UDP galactose epimerase * Uridine diphosphate Uridine diphosphate, abbreviated UDP, is a nucleotide diphosphate. It is an ester of pyrophosphoric acid with the nucleoside uridine. UDP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase uracil. UDP is an importa ... References Coenzymes Nucleotides {{biochemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactose
Galactose (, '' galacto-'' + '' -ose'', "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molecule linked with a glucose molecule forms a lactose molecule. Galactan is a polymeric form of galactose found in hemicellulose, and forming the core of the galactans, a class of natural polymeric carbohydrates. D-Galactose is also known as brain sugar since it is a component of glycoproteins (oligosaccharide-protein compounds) found in Nerve tissue, nerve tissue. Etymology The word ''galactose'' was coined by Charles Weissman in the mid-19th century and is derived from Greek ''galaktos'' (of milk) and the generic chemical suffix for sugars ''-ose''. The etymology is comparable to that of the word '' lactose'' in that both contain roots meaning "milk sugar". Lactose is a disaccharide of galactose plus glucose. Structure and isomerism Gal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactokinase
Galactokinase is an enzyme (phosphotransferase) that facilitates the phosphorylation of α-D-galactose to galactose 1-phosphate at the expense of one molecule of ATP. Galactokinase catalyzes the second step of the Leloir pathway, a metabolic pathway found in most organisms for the catabolism of α-D-galactose to glucose 1-phosphate. First isolated from mammalian liver, galactokinase has been studied extensively in yeast, archaea, plants, and humans. Structure Galactokinase is composed of two domains separated by a large cleft. The two regions are known as the N- and C-terminal domains, and the adenine ring of ATP binds in a hydrophobic pocket located at their interface. The N-terminal domain is marked by five strands of mixed beta-sheet and five alpha-helices, and the C-terminal domain is characterized by two layers of anti-parallel beta-sheets and six alpha-helices. Galactokinase does not belong to the sugar kinase family, but rather to a class of ATP-dependent enzymes kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactosemia
Galactosemia (British galactosaemia, from Greek γαλακτόζη + αίμα, meaning galactose + blood, accumulation of galactose in blood) is a rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly. Galactosemia follows an autosomal recessive mode of inheritance that confers a deficiency in an enzyme responsible for adequate galactose degradation. Friedrich Goppert (1870–1927), a German physician, first described the disease in 1917, with its cause as a defect in galactose metabolism being identified by a group led by Herman Kalckar in 1956. Galactosemia was the second disorder found to be detectable through newborn screening methods by Robert Guthrie. Its incidence is about 1 per 60,000 births for people of European ancestry. In other populations the incidence rate differs. Galactosaemia is about one hundred times more common (1:480 births) in the Irish Traveller population. Symptoms Adults Infants Infan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactose-1-phosphate Uridylyltransferase
Galactose-1-phosphate uridylyltransferase (or GALT, G1PUT) is an enzyme () responsible for converting ingested galactose to glucose. Galactose-1-phosphate uridylyltransferase (GALT) catalyzes the second step of the Leloir pathway of galactose metabolism, namely: :UDP-glucose + galactose 1-phosphate \rightleftharpoons glucose 1-phosphate + UDP-galactose The expression of GALT is controlled by the actions of the FOXO3 gene. The absence of this enzyme results in classic galactosemia in humans and can be fatal in the newborn period if lactose is not removed from the diet. The pathophysiology of galactosemia has not been clearly defined. Image:D-galactose Fischer.png, galactose Image:D-glucose-chain-2D-Fischer.png, glucose Mechanism GALT catalyzes the second reaction of the Leloir pathway of galactose metabolism through ping pong bi-bi kinetics with a double displacement mechanism. This means that the net reaction consists of two reactants and two products (see the reaction ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organophosphates
In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered as esters of phosphoric acid. Like most functional groups, organophosphates occur in a diverse range of forms, with important examples including key biomolecules such as DNA, RNA and ATP, as well as many insecticides, herbicides, nerve agents and flame retardants. OPEs have been widely used in various products as flame retardants, plasticizers, and performance additives to engine oil. The popularity of OPEs as flame retardants came as a substitution for the highly regulated brominated flame retardants. The low cost of production and compatibility to diverse polymers made OPEs to be widely used in industry including textile, furniture, electronics as plasticizers and flame retardants. These compounds are added to the final product physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
