D-Ribitol 5-phosphate

This enzyme [EC 2.7.7.40], also known as CDP-ribitol pyrophosphorylase, catalyzes the reaction of CTP with D-ribitol 5-phosphate to produce CDP-ribitol and pyrophosphate (or, diphosphate). 

This enzyme [EC 1.1.1.137] catalyzes the reaction of d-ribitol 5-phosphate with NAD(P)+ to produce D-ribulose 5-phosphate and NAD(P)H. 

An atypical ribitol TA was found in a capsule of the Gram-negative bacteria Haemophilus influenza type a18) (5). The monomeric unit of this polymer consists of 4-0-P-D-glucopyranosyl-D-ribitol-5-phosphate linked at the 4 position in the sugar residue. 

Show that L-ribitol 1-phosphate is identical with D-ribitol 5-phosphate. 

All carbon atoms of ribitol are in the same state of oxidation, and the carbon chain can be numbered from either end. If numbered as shown in (a) below, and assuming C-l was derived from an aldehyde, then the compound would be related to D-ribose and can be called D-ribitol. D-Ribitol 5-phosphate would be as shown in (b). However, if C-5 was derived from an aldehyde, then the compound would be related... 

In another example, the formation89 of racemic 1,4-anhydroribitol by the action of dilute hydrochloric acid for 20 hours at 100° on D-ribitol 1-phosphate has likewise been assumed to take place by protonation of the oxygen atom of the ester function, followed by an intramolecular substitution by the hydroxyl group on C-4. Formation of this protonated phosphoric ester likewise explains the ra-cemization observed, caused by partial migration of the ester group at C-l to C-5. 

The competitive inhibition of aldolase by a number of structural analogs of D-ftuctose 1,6-diphosphate has been investigated.120 Among these analogs were 1,4-anhydro-DL-ribitol 5-phosphate, 1,4-anhydro-DL-xylitol 5-phosphate, 1,4-anhydro-D-arabinitol 5-phosphate, 2,5-anhydro-D-mannitol 1,6-diphosphate, and 2,5-anhydro-D-glucitol 1,6-diphosphate. Their respective, enzyme-inhibitor,... 

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... 

The action of ammonia on cytidine ribitol pyrophosphate (III) gave a cyclic phosphate IX which was oxidized by periodate and bromine to yield X, the cyclic 2,3-0-phosphate of glyceronic acid. This substance was purified by paper chromatography, and hydrolyzed with acid to the 2-phos-phate (XI) and 3-phosphate (XII) of D-glyceronic acid. These substances were utilized by a multi-enzyme system from rabbit muscle which degrades carbohydrates by way of the Embden-Meyerhof pathway. The ribitol phosphate (VII) is therefore L-ribitol 1-phosphate (o-ribitol 5-phosphate). ... 

Synthetic cytidine ribitol pyrophosphate was prepared by condensing cytidine 5-phosphate and D-ribose 5-phosphate in the presence of dicyclohexylcarbodiimide, followed by the reduction of the cytidine D-ribose pyrophosphate with sodium borohydride. 

The racemization apparently takes place before hydrolysis. Similar results have been obtained with D-xylitol 5-phosphate and n-mannitol 6-phosphate. 1,4-Anhydro-ribitol is also formed from the treatment of ribitol with dilute mineral acid. However, since the anhydro compounds are produced more readily from the phosphates than from the unsubstituted alditols, it has been suggested that the latter compounds are not formed as intermediate products. The mechanism of this reaction has been explained by assuming protonation of the ester oxygen atom, with subsequent intra-... 

Ribitol 2,3,4-Tribenzoyl, 1,5-diphosphate, R-94 9-Ribofuranosyluric acid p-D-/orm 5 -Phosphate, R-124 Ribose 1-diphosphate 5-phosphate a-D-Furanose rm, R-141 Ribose 1-diphosphate 5-phosphate, R-141 Ribose a-D-Furanose-ybrm 1-Phosphate, R-138 Ribose a-D-Furanose-ybrm 5-Phosphate, R-138 Tagatose D-form 6-Phosphate, T-2... 

D-Ribitol i-phosphate has been obtained by reduction of ribose 5-phosphate and by hydrolysis of cytidine diphosphate ribitol . It is formed enzymically from ribitol and ATP . ... 

The isomerism existing between the pairs of nucleotides was attributed to the different locations of the phosphoryl residues in the carbohydrate part of the parent nucleoside,49 63 since, for instance, the isomeric adenylic acids are both hydrolyzed by acids to adenine, and by alkalis or kidney phosphatase to adenosine. Neither is identical with adenosine 5-phosphate since they are not deaminated by adenylic-acid deaminase,68 60 and are both more labile to acids than is muscle adenylic acid. An alternative explanation of the isomerism was put forward by Doherty.61 He was able, by a process of transglycosidation, to convert adenylic acids a" and 6 to benzyl D-riboside phosphates which were then hydrogenated to optically inactive ribitol phosphates. He concluded from this that both isomers are 3-phosphates and that the isomerism is due to different configurations at the anomeric position. This evidence is, however, open to the same criticism detailed above in connection with the work of Levene and coworkers. Further work has amply justified the original conclusion regarding the nature of the isomerism, since it has been found that, in all four cases, a and 6 isomers give rise to the same nucleoside on enzymic hydrolysis.62 62 63 It was therefore evident that the isomeric nucleotides are 2- and 3-phosphates, since they are demonstrably different from the known 5-phosphates. The decision as to which of the pair is the 2- and which the 3-phosphate proved to be a difficult one. The problem is complicated by the fact that the a and b" nucleotides are readily interconvertible.64,64... 

A repeating unit for S6 was proposed by Rebers and Heidelberger,29 as discussed in Ref. 1. The only features not determined were the structure and configuration of a ribitol phosphate moiety. From biosynthetic considerations,6 the phosphate group should be linked to 0-5 of D-ribitol, and the structure should, therefore, be that depicted in 10. 

The phosphate of ethylene glycol must derive from the ribitol phosphate moiety, which consequently is phosphorylated at a primary position, assumed to be 0-5 of (pro-D)-ribitol for biosynthetic reasons. In the proposed structure for the S10A repeating-unit (14), the anomeric natures of the sugar residues were not determined. The optical rotations of S10A and the hexasaccharide, [a]D +12° and +11°, respectively, indicate that they contain both a- and /3-D-linked sugar residues. 

D-Ribono-1,4-lactone (1) readily condenses with acetone, under acidic catalysis with mineral acids or anhydrous copper sulfate, to give 2,3-0-isopropylidene-D-ribono-1,4-lactone (16a), which was employed for the synthesis of 5-deoxy and 5-0-substituted derivatives of D-ribono- 1,4-lactone and D-ribitol (24). Acid removal of the 1,3-dioxolane protecting group gave products having probable inhibitory activity of arabinose 5-phosphate isomerase (25). Other applications of 16a for the synthesis of natural products will be discussed later. 

Alkaline hydrolysis of the teichoic acid gave a mixture of monophosphates of 0-D-glucosyl-D-ribitol (XVII), only traces of diphosphates, and no phos-pho diesters. Removal of D-glucose by 8-D-glucosidase gave ribitol 1-phosphate and ribitol 2-phosphate (and no ribitol 3-phosphate). Thus, the phospho diester linkages are at positions 1 and 5 in the polymer. 

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