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A rare sugar is a sugar that occurs in limited quantities in nature. [2] Rare sugars can be made using enzymes, choosing which enzymes to use if you know the substrate can be aided by the Izumoring-strategy. [3]
Specific examples of rare sugars are:
Enzymes are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called enzymology and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties.
Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid (carbamic acid is unstable), with the chemical formula NH2‐CH2‐COOH. Glycine is one of the proteinogenic amino acids. It is encoded by all the codons starting with GG (GGU, GGC, GGA, GGG). Glycine is integral to the formation of alpha-helices in secondary protein structure due to its compact form. For the same reason, it is the most abundant amino acid in collagen triple-helices. Glycine is also an inhibitory neurotransmitter – interference with its release within the spinal cord (such as during a Clostridium tetani infection) can cause spastic paralysis due to uninhibited muscle contraction.
Glucose is a sugar with the molecular formula C6H12O6. 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.
Galactose, 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.
A sugar substitute is a food additive that provides a sweetness like that of sugar while containing significantly less food energy than sugar-based sweeteners, making it a zero-calorie or low-calorie sweetener. Artificial sweeteners may be derived through manufacturing of plant extracts or processed by chemical synthesis. Sugar substitute products are commercially available in various forms, such as small pills, powders, and packets.
In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is C6H12O6, and their molecular weight is 180.156 g/mol.
Cellulase is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharides:
Safrole is an organic compound with the formula CH2O2C6H3CH2CH=CH2. It is a colorless oily liquid, although impure samples can appear yellow. A member of the phenylpropanoid family of natural products, it is found in sassafras plants, among others. Small amounts are found in a wide variety of plants, where it functions as a natural antifeedant. Ocotea pretiosa, which grows in Brazil, and Sassafras albidum, which grows in eastern North America, are the main natural sources of safrole. It has a characteristic "sweet-shop" aroma.
Sorbose is a ketose belonging to the group of sugars known as monosaccharides. It has a sweetness that is equivalent to sucrose. The commercial production of vitamin C often begins with sorbose. L-Sorbose is the configuration of the naturally occurring sugar. It can be prepared from inexpensive O-benzylglucose.
Xylose is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional group. It is derived from hemicellulose, one of the main constituents of biomass. Like most sugars, it can adopt several structures depending on conditions. With its free aldehyde group, it is a reducing sugar.
Tagatose is a hexose monosaccharide. It is found in small quantities in a variety of foods, and has attracted attention as an alternative sweetener. It is often found in dairy products, because it is formed when milk is heated. It is similar in texture and appearance to sucrose :215 and is 92% as sweet,:198 but with only 38% of the calories.:209 Tagatose is generally recognized as safe by the Food and Agriculture Organization and the World Health Organization, and has been since 2001. Since it is metabolized differently from sucrose, tagatose has a minimal effect on blood glucose and insulin levels. Tagatose is also approved as a tooth-friendly ingredient for dental products. Consumption of more than about 30 grams of tagatose in a dose may cause gastric disturbance in some people, as it is mostly processed in the large intestine, similar to soluble fiber.:214
D-Psicose (C6H12O6), also known as D-allulose, or simply allulose, is a low-calorie epimer of the monosaccharide sugar fructose, used by some major commercial food and beverage manufacturers as a low-calorie sweetener. First identified in wheat in the 1940s, allulose is naturally present in small quantities in certain foods.
Gentiobiose is a disaccharide composed of two units of D-glucose joined with a β(1->6) linkage. It is a white crystalline solid that is soluble in water or hot methanol. Gentiobiose is incorporated into the chemical structure of crocin, the chemical compound that gives saffron its color. It is a product of the caramelization of glucose. During a starch hydrolysis process for glucose syrup, gentiobiose, which has bitterness, is formed as an undesirable product through the acid-catalyzed condensation reaction of two D-glucose molecules. One β-D-glucose unit elongation of the bitter disaccharide reduces its bitterness by a fifth, as determined by human volunteers using the trimer, gentiotriose. Gentiobiose is also produced via enzymatic hydrolysis of glucans, including pustulan and β-1,3-1,6-glucan.
Glycosyltransferases are enzymes that establish natural glycosidic linkages. They catalyze the transfer of saccharide moieties from an activated nucleotide sugar to a nucleophilic glycosyl acceptor molecule, the nucleophile of which can be oxygen- carbon-, nitrogen-, or sulfur-based.
The avermectins are a series of drugs and pesticides used to treat parasitic worms and insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by Streptomyces avermitilis, a soil actinomycete. Eight different avermectins were isolated in four pairs of homologue compounds, with a major (a-component) and minor (b-component) component usually in ratios of 80:20 to 90:10. Other anthelmintics derived from the avermectins include ivermectin, selamectin, doramectin, eprinomectin, and abamectin.
In enzymology, a pyranose oxidase (EC 1.1.3.10) is an enzyme that catalyzes the chemical reaction
Nucleotide sugars are the activated forms of monosaccharides. Nucleotide sugars act as glycosyl donors in glycosylation reactions. Those reactions are catalyzed by a group of enzymes called glycosyltransferases.
The Reichstein process in chemistry is a combined chemical and microbial method for the production of ascorbic acid from D-glucose that takes place in several steps. This process was devised by Nobel Prize winner Tadeusz Reichstein and his colleagues in 1933 while working in the laboratory of the ETH in Zürich.
Glycorandomization, is a drug discovery and drug development technology platform to enable the rapid diversification of bioactive small molecules, drug leads and/or approved drugs through the attachment of sugars. Initially developed as a facile method to manipulate carbohydrate substitutions of naturally occurring glycosides to afford the corresponding differentially glycosylated natural product libraries, glycorandomization applications have expanded to include both small molecules and even macromolecules (proteins). Also referred to as 'glycodiversification', glycorandomization has led to the discovery of new glycoside analogs which display improvements in potency, selectivity and/or ADMET as compared to the parent molecule.
Ribose is a simple sugar and carbohydrate with molecular formula C5H10O5 and the linear-form composition H−(C=O)−(CHOH)4−H. The naturally-occurring form, d-ribose, is a component of the ribonucleotides from which RNA is built, and so this compound is necessary for coding, decoding, regulation and expression of genes. It has a structural analog, deoxyribose, which is a similarly essential component of DNA. l-ribose is an unnatural sugar that was first prepared by Emil Fischer and Oscar Piloty in 1891. It was not until 1909 that Phoebus Levene and Walter Jacobs recognised that d-ribose was a natural product, the enantiomer of Fischer and Piloty's product, and an essential component of nucleic acids. Fischer chose the name "ribose" as it is a partial rearrangement of the name of another sugar, arabinose, of which ribose is an epimer at the 2' carbon; both names also relate to gum arabic, from which arabinose was first isolated and from which they prepared l-ribose.
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