Ribose 5-phosphate, acid hydrolysis

The 3- and 5-phosphates of D-ribose have both been obtained through the hydrolysis of naturally occurring ribosides. In 1908 Levene and Jacobs122 subjected the barium salt of inosinic acid to acid hydrolysis and obtained a pentose phosphate as its barium salt. Shortly thereafter the same authors78 showed that, under the conditions which normally convert a pentose to a pentaric acid, this phosphate was oxidized only to a phosphorylated D-ribonic acid and it was evident, therefore, that... 

Phosphorylation of XLVII with phosphorus oxychloride in pyridine solution, followed by hydrolysis to remove the methyl and isopropylidene residues, gave D-ribose 5-phosphate (XLVIII) which, as its barium salt, was found to be identical with the barium salt of the D-ribose phosphate from inosinic acid. By way of further confirmation of the structure of D-ribose 5-phosphate, Levene, Harris and Stiller129 showed that in methanolic hydrogen chloride solution both the natural and synthetic material mutarotated in a manner characteristic of a sugar which can form only a furanoside. 

In 1932 Levene and Harris128 showed that the hydrolysis of xanthylic acid gave rise to the formation of a D-ribose phosphate which was not identical with the known D-ribose 5-phosphate. Since xanthylic acid is the monophosphate derivative of a ribofuranoside of xanthine it followed that the new phosphate was either D-ribose 2-phosphate or the 3-isomer (L). Shortly thereafter the same authors129 succeeded in reducing the new D-ribose phosphate with hydrogen in the presence of platinum oxide to a ribitol phosphoric acid (LI) which was completely... 

Histidine can be prepared from imidazole as in Scheme 117. It is a basic amino acid, the biosynthesis of which appears to involve adenosine 5 -phosphate, ribose phosphate and glutamine (which supplies a nitrogen for the imidazole ring) (Scheme 118). Histidine is one of the most important amino acids and has involvement in such biological processes as ester hydrolysis, acylation and (by virtue of its complexing power with iron) oxygen... 

Nucleosides and nucleotides are combinations of a base with a sugar. A nucleoside is an N-glycoside formed between a base and a sugar (usually ribose or deoxyribose). A nucleotide is a phosphate ester of a nucleoside. DNA nucleotides are more stable to acid hydrolysis of the glycosidic bond, which is one reason tfrat DNA has superceded RNA as the main genetic storage molecule it is less prone to mutation. 

Inosinic acid (1), the first nucleotide to be discovered, was isolated over a century ago from beef extract by Liebig. Mild, acid hydrolysis of this nucleotide yielded a ribose phosphate (2) which, by oxidation with nitric acid, gave a ribonic acid phosphate (3), but not a ribaric acid phosphate. These studies by Levene and his associates showed that the phosphoric (phospho) group is bound to the 5-hydroxyl group of the ribosyl moiety in 1 hence, inosinic acid is inosine 5 -phosphate. Adenylic acid (4), isolated from muscle, was converted enzymically (by adenylic... 

It is now known that mild, alkaline hydrolysis of ribonucleic acids yields mixtures of the 2 - and 3 -phosphates of ribonucleosides, although it had earlier been believed that only the 3 -phosphate derivatives are produced. For example, it was reported that guanylic acid (6), obtained from ribonucleic acid hydrolysates, is deaminated with nitrous acid to xanthylic acid (7), which was hydrolyzed at pH 1.9 to a ribose phosphate... 

Ribose phosphates can be obtained from nucleotides. Mild acid hydrolysis of inosinic acid (12.19a), for example, yields ribose-5 -phosphate and inosine whereas neutral hydrolysis yields inositol and phosphate. 

Amino acid analysis of a strong acid hydrolysate (2 N HCl at 100° C for 3 h) identified only glutamic acid and this was confirmed by gas chromatography-mass spectroscopy (Fig. 4). Mild acid hydrolysis (0.5 N HCl at 80°C for 1 h) followed by direct insertion mass spectroscopy gave a spectrum identical to authentic ribose-5-phosphate (Fig. 5). Borate electrophoresis of the alditol derived from the stored material and of its acid... 

In 1928 Lohmann isolated a compound from muscle tissue extracts which consisted of adenosine esterified with 3 moles of phosphoric acid (127). Acid hydrolysis of the adenosine triphosphate (ATP) yielded 1 mole of adenine, 1 mole of ribose monophosphate, and 2 moles of phosphoric acid, whereas neutral hydrolysis gave adenosine 5 -phosphate (muscle adenylic... 

Acid hydrolysis of the coenzymes splits the glycosidic bond to the bases, as well as the pyrophosphate bridge. The products are thus nicotinamide, ribose-5-phosphate, and adenine. 

Lipid oxidation products and their reaction products with amino acids (proteins) have a considerable influence on the typical odour and taste of meat. Particularly significant aminocarboxylic acids include glutamic acid, alanine, threonine and lysine, guanidine compounds (creatine and creatinine), quaternary ammonium compounds (choline and carnitine), peptides (P-alanylhistidine peptides and some products of proteolysis), free nucleotides, nucleosides and their bases (especially inosine 5 -monophosphate, IMP), proteins, carboxylic acids (especially lactic acid), sugars (mainly glucose, fructose and their phosphates, ribose formed by hydrolysis of free nucleotides) and some vitamins (especially thiamine). Some of these compounds, such as glutamic acid and IMP, are additionally used as food additives, namely as flavour enhancers. 

D-Ribose 5-phosphate is a normal metabolite in plants and animals. It was first prepared by acid hydrolysis of inosinic acid or from adenosine 5 -phosphate . It is formed enzymically from ribose and ATP . Synthesis has been carried out by phosphorylating 2,3-isopropylidene-methyl-D-ribofuranoside °. ... 

Deoxy-D-ribose 5-phosphate has been obtained by the action of a nucleoside phosphorylase and a mutase on hypoxanthine , by enzymic condensation of triose phosphate and acetaldehyde and by enzymic phosphorylation of D-2-deoxyribose . Acid hydrolysis of deoxy-adenylic or deoxy-guanylic acid yields deoxyribose 5-phosphate . A chemical s)mthesis is available . 

The nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are biological polymers that act as chemical carriers of an organism s genetic information. Enzyme-catalyzed hydrolysis of nucleic acids yields nucleotides, the monomer units from which RNA and DNA are constructed. Further enzyme-catalyzed hydrolysis of the nucleotides yields nucleosides plus phosphate. Nucleosides, in turn, consist of a purine or pyrimidine base linked to Cl of an aldopentose sugar—ribose in RNA and 2-deoxyribose in DNA. The nucleotides are joined by phosphate links between the 5 phosphate of one nucleotide and the 3 hydroxyl on the sugar of another nucleotide. 

In standard conditions, the change in free enthalpy AG° (see p. 18) that occurs in the hydrolysis of phosphoric acid anhydride bonds amounts to -30 to -35 kj mol at pH 7. The particular anhydride bond of ATP that is cleaved only has a minor influence on AG° (1-2). Even the hydrolysis of diphosphate (also known as pyrophosphate 4) still yields more than -30 kJ mol . By contrast, cleavage of the ester bond between ribose and phosphate only provides -9 kJ mol (3). 

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