Uridine Monophosphates Research Articles

Heavy metal nucleotide interactions. 12. Competitive reactions in systems of four nucleotides with cis- or trans-diammineplatinum(II). Raman difference spectrophotometry of the relative nucleophilicity of guanosine, cytidine, adenosine, and uridine monophosphates and analogous DNA bases

Heavy metal nucleotide interactions. 12. Competitive reactions in systems of four nucleotides with cis- or trans-diammineplatinum(II). Raman difference spectrophotometry of the relative nucleophilicity of guanosine, cytidine, adenosine, and uridine monophosphates and analogous DNA bases

Isolation of cyclic 3′,5′-pyrimidine mononucleotides from bacterial culture fluids

Summary Cyclic 3′,5′-cytidine and 3′,5′-uridine monophosphates were isolated from culture fluid of Corynebacterium murisepticum or Microbacterium species both of which excrete a large amount of cyclic 3′,5′-adenosine monophosphate.

Separation of 2′- and 3′-mononucleotides of plant viral ribonucleic acids by an improved two-dimensional thin-layer chromatography

Thin-layer chromatography (TLC) has been used widely in qualitative as well as small-scale quantitative separation of complex mixtures of nucleotides and their derivatives (1–4). The use of DEAE-cellulose, 1 1 Abbreviations: RNA, ribonucleic acid. 2′,3′-UMP, 2′,3′-CMP, 2′,3′-AMP, 2′,3′-GMP, the 2′,3′-monophosphates of uridine, cytidine, adenosine, and guanosine, respectively. MN300G, cellulose powder with CaSO 4·2 1 H 2O as binder. PPO, 2,5-diphenyloxazole. PEI, polyethyleneimine. DEAE, diethylaminoethyl. Sephadex, polyphosphate cellulose, phosphocellulose, silica gel, ECTEOLA-cellulose, PEI-cellulose, and polyamide as layering materials has been reported (1); however, cellulose powder is the most used layering material. The recognized advantages of TLC, namely, convenience, sensitivity, and short developing time as compared with paper chromatography, have been clearly demonstrated in nucleic acid studies (5). Sharper separations of nucleotides, nucleosides, and bases have been observed with cellulose layers (5). This paper describes a new two-dimensional TLC procedure to separate 2′- and 3′-nucleotide isomers of the mononucleotides derived from the ribonucleic acids. This method has been employed successfully in the analysis of base composition of plant viral RNA. Separation of the nucleosides was also achieved with this method.

Effectors of purified adenyl cyclase from Streptococcus salivarius

The activity of highly purified (3200-fold) adenyl cyclase from Streptococcus salivarius was examined in the presence and absence of P i, inorganic pyrophosphate, nucleotides and glycolytic intermediates. The enzyme was inhibited by P i, ADP and all the triphosphates and monophosphates of guanosine, uridine, inosine and cytidine; inhibition was completely competitive. The inhibition in the presence of PP i was partially competitive, while AMP produced inhibition of the mixed type, i.e., partially competitive and completely noncompetitive. PP i was the most potent inhibitor ( K i = 0.23 m m) followed by ADP ( K i = 0.43 m m), GTP ( K i = 0.52 m m) and UTP ( K i = 0.60 m m). Severe inhibition of the enzyme was also observed in the presence of the diphosphate and sugar nucleotides of the above bases at concentrations between 0.1 and 5 m m, when tested at one substrate concentration (ATP = 0.6 m m). The respective cyclic 3′,5′-nucleoside monophosphates were, however, only slightly inhibitory (maximum 11%). While the nucleotides were generally inhibitory, the activity of the enzyme was variable in the presence of various glycolytic intermediates. Weak activation of adenyl cyclase activity was observed with glucose-6-P, glucose-1-P, 2-P-glycerate and pyruvate. 2-P-glycerate required the lowest concentration for half maximal activation ( K a = 0.13 m m) followed by glucose-1-P (0.24 m m), glucose-6-P (0.55 m m) and pyruvate (1.12 m m). These compounds increased the V of the enzyme without affecting the apparent K m for ATP. Fructose-6-P, fructose-1,6-P 2, glyceraldehyde-3-P and P-enolpyruvate inhibited or activated the enzyme depending upon the concentration of the compound used. Both the apparent K m for ATP as well as the V were altered by fructose-6-P and fructose-1,6-P 2. However, activating concentrations of glyceraldehyde-3-P and P-enolpyruvate increased the V without affecting the apparent K m , whereas inhibiting concentrations decreased the V and increased the K m for the substrate.

Cyclic 3′,5′-nucleotide phosphodiesterase of Serratia marcescens

1. 1. A cyclic 3′,5′-nucleotide phosphodiesterase from the cells of Serratia marcescens was purified over 1000-fold. The purified preparation showed a pH maximum in the region of 7.5–8.5 in Tris-HCl buffer, with a K m of 0.52 mM for adenosine cyclic 3′,5′-phosphate. Gel filtration on a Sephadex G-100 column gave the molecular weight of 51 000. 2. 2. The esterase did not require Mg 2+ nor Mn 2 for activity, but was stimulated by Fe 2+, Ca 2+ or Ba 2+. Imidazole did not stimulate the activity. 3. 3. The cyclic 3′,5′-nucleotide phosphodiesterase of S. marcescens was inhibited competitively by theophylline. The K i value was 8.3·10 −4 s M. Proflavine, 8-hydroxyquinoline, Zn 2+, Cu 2+, Ni 2+ and 5′-deoxy-5′-(dihydroxyphosphinylmethyl)-adenosine 3′-cyclic ester were also inhibitory. The last compound was the most powerful competitive inhibitor with a K i of 4.5·10 −6 M. ADP, AMP and GTP were also slightly inhibitory. 4. 4. The enzyme was specific for nucleoside cyclic 3′,5′-monophosphates. Besides cyclic 3′,5′-monophosphates of adenosine, guanosine, inosine, thymidine and uridine the enzyme could hydrolyze cytidine cyclic 3′,5′-monophosphate at a considerable rate.

Effect of Dietary 2-Acetylaminofluorene on Rat Liver Enzymes Involved in the Anabolism and Catabolism of Nucleic Acid Precursors

The activities of the following enzymes have been determined in the soluble fraction of liver from rats fed a special basal diet supplemented with the carcinogen 2-acetylaminof luorene for various lengths of time: aspartate carbamoyltransferase, deoxycytidylate deaminase, deoxythymidylate kinase, the kinases which phosphorylate deoxycytidine, deoxythymidine, deoxyadenosine, and uridine, the phosphohydrolases which dephosphorylate the 5′-monophosphates of deoxythymidine, deoxyuridine, deoxycytidine, uridine and cytidine, and acid and alkaline non-specific phosphatases. Histological studies of the livers have also been performed. The enzyme activities showed widely different variation patterns during acetylamino-fluorene feeding. The deoxyadenosine and uridine kinase activities were not affected by the carcinogen, whereas all the other anabolic enzymes tested increased in activity within the experimental period. Also, the dephosphorylation of the nucleotides and the activity level of the acid phosphatase we...

Organophosphates of urine, including adenosine 3′,5′-monophosphate and guanosine 3′,5′-monophosphate

The presence of organic phosphorus compounds in the urine of healthy rats has been investigated. The animals were administered [ 32P]phosphate intraperitoneally to facilitate recognition and study of the metabolically derived P-containing components. Some of the phosphorus compounds were found to be extracted into ether at pH 4, and were not studied in detail. Systematic investigation was confined to compounds in the aqueous phase that are adsorbed by Norit A, which has high affinity for compounds with conjugated double bonds. Compounds found in this fraction were the cyclic nucleotides adenosine 3′,5′-monophosphate (3′,5′-AMP) and guanosine 3′,5′-monophosphate (3′,5′-GMP), and three unidentified compounds recognized only by rather low 32P contents. Excretion rates of the 3′,5′-AMP and 3′,5′-GMP were about 18 and 4 μg per day per 100 g rat body weight, respectively. These rates were not affected by treatment of rats with terramycin and sulphasuxidine. The cyclic 3′,5′-monophosphates of cytidine and uridine and the 5′-monophosphates of adenosine, cytidine, guanosine and uridine were either absent in the urine or present at levels too low for detection. Attention was drawn to the fact that the currently characterized organophosphorus compounds of normal urine are all phosphodiesters bearing only one negative charge per molecule. Possible implications concerning the permeability of cell walls were discussed. The specific 32P activity of the 3′,5′-GMP of 24 h rat urine samples was only about 30 % as high as that of the 3′,5′-AMP. Comparison of this value with the results of prior kinetic data on labeling of the innermost P groups of GTP and ATP of rat liver suggested that the 3′,5′-GMP is synthesized metabolically from GTP by a cyclase reaction analogous to the reaction used by synthesis of 3′,5′-AMP from ATP in liver cells of dogs. The isotope dilution method was applied to analysis of normal human urine. It was found that in man 3′,5′-GMP is excreted at a rate of approx. 1 μmole per day.

Enzymes of Nucleic Acid Metabolism from Mung Bean Sprouts: II. THE SPECIFICITY OF 3‘-NUCLEOTIDASE ACTIVITY AND GENERAL PROPERTIES OF THE 3‘-NUCLEOTIDASE-RIBONUCLEASE M2 FRACTION

Abstract The 3'-nucleotidase present in mung bean sprouts was found to hydrolyze the 3'-monophosphates of adenosine, guanosine, uridine, and cytidine in the order 3'-AMP g 3'-GMP g 3'-UMP g 3'-CMP, and also to hydrolyze the 3'-phosphate group of coenzyme A, but showed no significant activity for 2'- or 5'-ribonucleotides or for several non-nucleotide phosphomonoesters. pH optima and the respective Km values for 3'-AMP, 3'-GMP, 3'-CMP, and 3'-UMP were determined. The 3'-nucleotidase and ribonuclease M2 were inactivated reversibly at pH 5 and by dialysis and irreversibly by ethylenediaminetetraacetate. Inactivation of both enzymes at pH 5 could be largely prevented by the presence of Zn++, while several other metal ions were ineffective. The optimal concentrations of Zn++ for preventing inactivation were considerably different for the 3'-nucleotidase and RNase M2. The two enzyme activities were similarly inactivated by heat at pH 5 and 7.5. The pH optimum of RNase M2 was pH 5 with no Zn++ present, but dropped to pH 4.5 in the presence of 5 x 10-5 m Zn++, which also greatly increased its activity in the pH range 3.5 to 4.5. Several lines of evidence suggesting that the 3'-nucleotidase and RNase M2 activities may be due to the same protein are presented.

Distribution, properties and specificity of polynucleotide phosphorylase in wheat roots

The presence of polynucleotide phosphorylase, which catalyses the polymerization of ribonucleoside diphosphates and the 32P-ADP exchange, was demonstrated in wheat roots. This enzyme was found to be active in nuclear, mitochondrial, ribosomal and soluble subcellular fractions. The enzymatic activities of these fractions differed in their K m values, pH and temperature relations and in their stability. RNAase and DNAase (EC 3.1.4.5) had no effect on poly-A formation; (2-chloroethy)-trimethyl-ammonium chloride and 2,4-dichlorobenzyl-tributylphosphonium chloride stimulated the polymerization up to 50%. The enzyme synthesized homopolymers and copolymers of adenosine, guanosine, cytidine and uridine monophosphates from corresponding diphosphates. The rates of formation of poly-A, poly-G, poly-C and poly-U as well as the composition of the copolymers were specific for each subcellular fraction.

Nucleotide and nucleic acid metabolism in developing amphibian embryos: I. Isolation and chemical identification of acid-soluble nucleotides

1. 1. Eight acid-soluble nucleotides from amphibian eggs have been separated chromatographically and chemically identified. 2. 2. The nucleotides include the monophosphates of cytosine, adenosine, guanosine, and uridine; the diphosphate of adenosine; the triphosphates of adenosine, guanosine, and uridine. 3. 3. Preliminary P 32 incorporation data indicate that the AMP-ATP system is highly active in amphibian eggs.