Carbohydrate phosphoric acid ester

Catalyze the hydrolysis of carbohydrates, Upids, proteins, or phosphoric acids esters by breaking single bond and add water across bond... 

Some of the naturally occurring carbohydrates are also found as glycosides with nonsugar components, whereas some others contain less common functional groups, such as deoxy-sugars, uronic acids, and sulfuric or phosphoric acid esters. 

Carbohydrate phosphoramidates Cyclic phosphoric acid esters... 

Free thiamine and its phosphoric acid esters occur in all foods, but only in some are they present in significant amounts (Table 5.8). In general, higher concentrations of thiamine (1-lOmg/kg) are found in foods that are rich in carbohydrates, which undergo intensive metaboHsm of sugars (cereals and legumes, as well as in pork meat and Hver). 

HLA Tarr. The MaiUard reaction in flesh foods. Food Technol 8 15-19, 1954. RL Macy, HD Naumann, ME Bailey. Water-soluble flavor and odor precursors of meat. I. Qualitative study of certain amino adds, carbohydrates, non-amino acid nitrogen compounds, and phosphoric acid esters of beef, pork, and lamb. J Food Sd 29 136-141, 1964. 

Phosphorus. Eighty-five percent of the phosphoms, the second most abundant element in the human body, is located in bones and teeth (24,35). Whereas there is constant exchange of calcium and phosphoms between bones and blood, there is very Httle turnover in teeth (25). The Ca P ratio in bones is constant at about 2 1. Every tissue and cell contains phosphoms, generally as a salt or ester of mono-, di-, or tribasic phosphoric acid, as phosphoHpids, or as phosphorylated sugars (24). Phosphoms is involved in a large number and wide variety of metaboHc functions. Examples are carbohydrate metaboHsm (36,37), adenosine triphosphate (ATP) from fatty acid metaboHsm (38), and oxidative phosphorylation (36,39). Common food sources rich in phosphoms are Hsted in Table 5 (see also Phosphorus compounds). 

Functional Groups aldehydes ketones alcohols alkyl groups and rings carboxylic and phosphoric acids and esters amines carboxylic acids amides carbohydrate heterocyclic bases phosphate esters... 

An alcohol can react with phosphoric acid to produce a phosphate ester iphosphoester). When two phosphate groups are joined, the resulting bond is a phosphoric anhydride bond. These two functional groups are important to the structure and fimction o( adenosine triphosphate (ATP), the universal energy currency of all cells. Cellular enzymes can carry out a reaction between a thiol and a carboxylic acid to produce a thioester. This reaction is essential for the activation of acyl groups in carbohydrate and fatty acid metabolism. Coenz)une A is the most important thiol involved in these pathways. 

Phosphorus occurs in a large number of natural products of complex composition. It is an important constituent of certain proteins, which will be described later, and of the lecithins (217). Many of these compounds are esters of phosphoric acid in which the alcohol in combination with the acid is glycerol or a carbohydrate. 

Esters of cellulose with interesting properties such as bioactivity and thermal and dissolution behavior can be obtained by esterification of cellulose with nitric acid in the presence of sulfuric acid, phosphoric acid, or acetic acid. Commercially important cellulose esters are cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. Cellulose esters of aliphatic, aromatic, bulky, and functionalized carboxylic acids can be synthesized through the activation of free acids in situ with tosyl chloride, iV,iV -carbonyldiimidazole, and iminium chloride under homogeneous acylation with DMA/LiCl or DMSO/TBAF. A wide range of cellulose esters that vary in their DS, various substituent distributions, and several desirable properties can be obtained through these reactions. Recently, a number of enzymes that degrade cellulose esters have been reported. Some of them are acetyl esterases, carbohydrate esterase (CE) family 1, and esterases of the CE 5 [169-172] family. 

Glyceraldehyde-3-phosphate, an important compound in the cellular oxidation of carbohydrates, is an ester of phosphoric acid and glyceraldehyde. 

The hydroxy groups of monosaccharides can behave as alcohols and react with acids to form esters. Esters formed from phosphoric acid and various monosaccharides are found in all cells, and some serve as important intermediates in carbohydrate metabolism. The... 

Amide bonds are found in many proteins. One is the acyl carrier protein of Escherichia coli (see 90), which contains the peptide backbone, and a 4 -phosphopantetheine unit (in violet in the illustration) is attached to a serine residue. Note the amine bonds in the pantothenic acid unit and also the 0-P=0 unit, which is a phosphate ester (an ester of phosphoric acid). An acyl carrier protein is involved in fatty acid synthesis, linking acetyl and malonyl groups from acetyl coenzyme A and malonyl coenzyme A to form P-keto acid acyl carrier protein (abbreviated as ACP). The widely utilized acetyl CoA is an ester (91) attached to coenzyme A. Acetyl CoA is a key intermediate in aerobic intermediary metabolism of carbohydrates, lipids, and some amino acids. 

As shown in earlier chapters, there are five bases that will be considered. Their structures are shown in Figure 14.1. All of these, when found in DNA (A, G, C, and T) and RNA (A, G, C, and U), occur attached to their respective (ribose [RNAJor deoxyribose [DNA]) carbohydrate esters of phosphoric acid. These derivatives have also been introduced in Chapter 12 and are discussed further below. 

Of course, the potential for ionic liquids being generated from glycosides and related carbohydrate-derived cations with tosylate anions remains. These have been observed in several instances, and the pwssibiUty remains for additional species to have similar behavior and characteristics. There are also possibilities, including the tunability of characteristics, through the use of mono-esters of phosphoric acid or sulfuric add (see Figure 15), again... 

Various investigations have supplied ample experimental justification for the analogy drawn by Brown and Todd between simple hydroxylated dialkyl phosphoric esters and polynucleotides. With the object of applying classical methods of carbohydrate chemistry, yeast ribonucleic acid was methylated, and the carbohydrates obtained after hydrolysis were examined.200- 201 D-Ribose and mono-O-methyl- and di-O-methyl-D-riboses were... 

Like all carbohydrates, cellulose possesses the clearly marked prominent properties of an alcohol owing to the presence of hydroxyl (alcoholic) groups. The presence of those groups explains the ability of cellulose to form esters with nitric acid and with acetic acid which have attained great practical importance, and also with sulphuric, phosphoric and different organic adds, as well as the formation of cellulose ethers. 

Nucleotides are generally defined as phosphoric esters (of the carbohydrate moiety) of nucleosides. In polymerized forms (involving phospho-diester linkages), the nucleotides constitute the nucleic acids, which are fundamental components of all cells and viruses. Nucleotides also occur as mixed anhydrides, such as adenosine 5 -triphosphate and uridine 5 -(q -d-glucopyranosyl pyrophosphate), which comprise an important class of... 

A whole class of fascinating, acidic and ester polysaccharides of biological significance awaits exploration by x-ray diffraction. Typical of these compounds are the pneumococcal polysaccharides, whose structures are highly specific, albeit they contain a wide variety of carbohydrate moieties, of which D-glucuronic acid is a common one. Occasionally, a phosphoric ester link between moieties is an integral part of the complex, repeating... 

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