Disease relevance of arabinose-5P

• The Escherichia coli ADP-ribose pyrophosphatase, a Nudix enzyme, catalyzes the hydrolysis of ADP-ribose to ribose-5-P and AMP, compounds that can be recycled as part of nucleotide metabolism [1].
• We have determined the crystal structures of Rpi from Thermus thermophilus HB8 in complex with the open chain form of the substrate R5P and the open chain form of the C2 epimeric inhibitor arabinose-5-phosphate as well as the apo form at high resolution [2].
• Mycobacterium tuberculosis ribose-5-phosphate isomerase has a known fold, but a novel active site [3].
• Although levels of ribose-5P and (ribulose-5P+xylulose-5P) rose several fold during ischemia with minor changes in sedoheptulose-7P, demonstrating an active PPP in the heart, PC did not affect these levels [4].
• The effect of temperature on ribose-5-phosphate isomerase from a mesophile, Thiobacillus thioparus, and a thermophile, Bacillus caldolyticus [5].

High impact information on arabinose-5P

• TAL-H is a key enzyme of the nonoxidative pentose phosphate pathway (PPP) providing ribose-5-phosphate for nucleic acid synthesis and NADPH for lipid biosynthesis [6].
• These results may be taken to suggest that ribose-5-phosphate availability is indeed not limiting for PRPP generation under physiological conditions [7].
• By incubating the patient's lymphoblasts and erythrocytes with ribose-5-phosphate and subsequently analyzing phosphate sugar metabolites, we discovered a deficiency of transaldolase [8].
• Extracts from this cell line had normal ammonia ribose-5-phosphate aminotransferase activity [9].
• Covalently bound adducts of ply(L-lysine), bovine serum albumin, lysine rich histone (f1) and deoxyribonucleotidase I (DNase, EC 3.1.4.5) with adenosine diphosphoribose and ribose-5-phosphate were prepared at pH 7.4 and 9 [10].

Chemical compound and disease context of arabinose-5P

• 3-Deoxy-D-manno-octulosonate-8-phosphate synthase from Escherichia coli. Model of binding of phosphoenolpyruvate and D-arabinose-5-phosphate [11].
• The cDNA of kdsA could not complement Escherichia coli K-12 strain AB3257, which is defective in all three isoenzymes (AroFGH) of 3-deoxy-D-arabino-hept-2-ulosonate-7-phosphate (Dha-7-P) synthase (EC 4.1.2.15), and neither D-erythrose-4-phosphate nor D-ribose-5-phosphate could substitute for D-arabinose-5-phosphate in vitro [12].
• The rates of formation (from ribose-5-phosphate and NH3) and degradation of PRA were also measured using E. coli GAR synthetase (recently cloned, overproduced and purified to homogeneity) as a trap [13].
• Structure of Escherichia coli ribose-5-phosphate isomerase: a ubiquitous enzyme of the pentose phosphate pathway and the Calvin cycle [14].
• Phosphoribosylpyrophosphate synthetase (ribose-5-phosphate pyrophosphokinase) from Salmonella typhimurium [15].

Biological context of arabinose-5P

• The results suggest active site locations for the sequence-conserved and TNP-modified lysine residues, with Lys-26 interacting with the ribose-5-phosphate moiety of OMP and PRPP, and Lys-100 and Lys-103 interacting with the pyrophosphate moiety of PRPP [16].
• DHEA is a powerful inhibitor of glucose-6-phosphate dehydrogenase (G6PDH), suggesting that its inhibiting effect in carcinogenesis may be due to a lack of NADPH and ribose-5-phosphate production for deoxyribonucleotide synthesis and subsequent DNA replication [17].
• Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA, which encodes ribose-5-phosphate isomerase [18].
• The hexose monophosphate shunt (HMS) produces NADPH for reductive antioxidant protection and for metabolic regulation, as well as ribose-5-phosphate needed for the synthesis of nucleic acids [19].
• We suggest that the proposed shuttle may function to increase ribose-5-phosphate synthesis by the oxidative limb of the pentose phosphate pathway and inturn increase PP-ribose-P and purine synthesis during the initiation of cell growth [20].

Anatomical context of arabinose-5P

• In order to identify new forms of enzyme abnormalities associated with excessive purine synthesis, the value of a proposed classification scheme requiring measurement of PRPP and ribose-5-phosphate concentration and generation is being assessed in cultured fibroblasts [21].
• We conclude that the inhibition of gap junction communication induces astrocyte proliferation, resulting in an enhancement of glucose uptake and its utilization through the pentose phosphate pathway to provide ribose-5-phosphate for the synthesis of nucleic acids [22].
• Furthermore, the noticeable increase in the hepatocyte population involved in DNA replication parallel to G6PDH activity suggests that G6PDH, through ribose-5-phosphate, might also be involved in the processes of DNA synthesis and repair [23].
• The isotopomer analysis of the lactate, alanine, glutamate, proline, serine, glycine, malate and ribose-5-phosphate moiety of nucleotides has allowed original integrated information regarding the pentose phosphate pathway, TCA cycle, and amino acid metabolism in proliferating human leukemia T cells to be obtained [24].
• D-ribose-5-phosphate isomerase from skeletal muscle [25].

Associations of arabinose-5P with other chemical compounds

• Ribose-5-phosphate isomerase (Rpi) acts as a key enzyme in the oxidative and reductive pentose-phosphate pathways for the conversion of ribose-5-phosphate (R5P) to ribulose-5-phosphate and vice versa [2].
• The 19-kDa protein containing the Nudix box, GX5EX7REUXEEXGU, has been purified and identified as a highly specific enzyme catalyzing the Mg2+-dependent hydrolysis of ADP-ribose according to the equation: ADP-ribose + H2O --> AMP + ribose-5-phosphate [26].
• Ribokinase phosphorylates ribose to form ribose-5-phosphate in the presence of ATP and magnesium [27].
• In addition to the bound Cd(2+), the Cd(2+)-PRPPsase structure contains a sulfate ion in the regulatory site, a sulfate ion at the ribose-5-phosphate binding site, and an AMP moiety at the ATP binding site [28].
• NG108-15 cells released orthophosphate from 2'- and 3'-AMP as well as from ribose-5-phosphate and ss-glycerophosphate, indicating that NG108-15 cells express ecto-ALP [29].

Gene context of arabinose-5P

• Crystal structure of a ribose-5-phosphate isomerase RpiB (TM1080) from Thermotoga maritima at 1.90 A resolution [30].
• Crystal structure of the S. cerevisiae D-ribose-5-phosphate isomerase: comparison with the archaeal and bacterial enzymes [31].
• The enzyme was finally detached from CM-cellulose by specific elution with a D-xylulose-5-phosphate/D-ribose-5-phosphate mixture and the isolated product exhibited a specific activity of about 10 units/mg protein at 37 degrees C. Transketolase preparations are contamination-free, except for a slight residual activity of phosphohexose isomerase [32].
• Ribose-5-phosphate-regulated pyruvate kinase (EC 2.7.1.40) was much less sensitive that PK I to the inhibitory effects of PF [33].
• Ribose-5-phosphate isomerase (RPI) catalyses the interconversion of ribose-5-phosphate and ribulose-5-phosphate in the reductive and oxidative pentose phosphate pathways in plants [34].

Analytical, diagnostic and therapeutic context of arabinose-5P

• D-ribose-5-phosphate isomerase from spinach: heterologous overexpression, purification, characterization, and site-directed mutagenesis of the recombinant enzyme [35].

References