Acetonitrile-based solvents: Their application in thin-layer chromatography of cyclic nucleotides, nucleosides, purine, and pyrimidines

Acetonitrile-based solvent mixtures have been applied to the separation of nucleotides, nucleosides, purines, pyrimidines, and cyclic nucleotides by thin-layer chromatography. The R_f's of over 35 compounds are presented. Development times with some of the systems were as low as 16 min. The use of acetonitrile-containing solvents in adenyl cyclase and cyclic phosphodiesterase assays and in the nucleotides and nucleic acid fields is discussed.     

Ligand-exchange chromatography of nucleotides,nucleosides, and nucleic acid bases

Ligand-exchange chromatography, with a copper-loaded chelating resin (Chelex 100), is a useful technique for the rapid separation of nucleic acid components. Nucleotides are not retained on the column and are eluted with water. Weakly basic nucleosides and bases are only weakly retained and can be resolved by elution with water. More basic nucleosides can be separated by elution with 1 N NH₄OH. Nucleic acid bases are more strongly retained but can be eluted and separated with 2.5 N NH₄OH.     

One-step chromatography method for efficient separation and purification of R-phycoerythrin from Polysiphonia urceolata

Phycoerythrins have been widely used in food, cosmetics, immunodiagnostics and analytical reagents. An efficient one-step chromatography method for purification of R-phycoerythrins from Polysiphonia urceolata was described in this paper. Pure R-phycoerythrin was obtained with an absorbance ratio A(565)/A(280) of 5.6 and a high recovery yield of 67.33% using a DEAE-Sepharose Fast Flow chromatography with a gradient elution of pH, alternative to common gradient elution of ionic strength. The absorption spectrum of R-phycoerythrin was characterized with three absorbance maxima at 565, 539 and 498 nm, respectively and the fluorescence emission spectrum at room temperature was measured to be 580 nm. The results of native-PAGE, and SDS-PAGE showed no contamination by other proteins in the phycoerythrin solution, which suggests an efficient method for the separation and purification of R-phycoerythrins from Polysiphonia urceolata.     

Reversed-phase boronate chromatography for the separation of O-methylribose nucleosides and aminoacyl-tRNAs

Boronate forms an anionic complex with the cis-2′,3′ hydroxyls of unsubstituted ribonucleosides and the 3′-terminal adenosine of unacylated tRNAs, but not with ribosesubstituted nucleosides such as 2′-O-methylnucleosides and aminoacyl-tRNAs. We have synthesized phenyl boronates with hydrophobic side chains of about 1-nm-long and coated inert 10-μm solid beads of polychlorotrifluoroethylene with this material. This matrix complexes easily with compounds containing free cis-hydroxyls, but not with their O-alkyl or O-acyl derivatives. This permits the separation of mammalian and bacterial amino-acyl-tRNAs from uncharged tRNAs and O-methyl nucleosides from ribose-unsubstituted nucleosides in one chromatographic step, as the substituted members of each group do not undergo boronate complex formation and are thus not as much retarded in passing through the column. Complex formation between ribofuranoses and the boronate matrix appears to be enhanced by the hydrophobic “tail” of the boronate compound, by the high ionic environment of the solvent, and by the hydrophobic nature of the inert support. This method of one-step purification of tRNAs on reversed-phase boronate columns has been tested for several tRNAs specific for amino acids of different hydrophobicity and ionic character. The results indicate that each tRNA tested can be purified with appreciable purity (70–95%) and high yield (80%). However, recovery of the queuine base containing aminoacyl-tRNAs is only about 6% of the applied material. Several other boronate matrices have also been synthesized using cellulose, agarose. Sepharose, or porous glass beads as the inert support with different lengths of the spacer arm. Cellulose with a 1-nm-long spacer arm is satisfactory not only for the separation of aminoacyl-tRNAs and O-methylribose nucleosides, but also for the separation as a group of tRNAs containing the base of Q, queuine. However, other inert supports are unsatisfactory because of a non-specific binding of the tRNAs.     

High-pressure liquid chromatography: I. Quantitative separation of purine and pyrimidine nucleosides and bases

A high-pressure liquid column chromatographic method has been developed for the separation and identification of ribonucleosides, deoxyribonucleosides, and bases. This method is capable of detecting these components at 1.0 to 5.0 ng applied; is reproducible under conditions of constant pressure, temperature, and pH; and is rapid, requiring about 30 min for a complete chromatographic separation of ribonucleosides from deoxyribonucleosides and from bases. These separations were carried out under different pH values and buffers, namely, phosphate buffer containing 2.5% methanol at pH 6.9 and 3.0 or 50 mm sodium borate buffer, pH 9.0. These different conditions were utilized to obtain more definitive identification and quantitation of normal metabolites and their counterparts, the antimetabolites. The advantage of this method is that the 20 naturally occurring components are separated from each other by an isocratic elution method, alleviating the need for a gradient elution system, which produces a drift in the baseline with increasing concentration of the eluting buffer, especially when the instrument is operating at maximum sensitivity, thus hindering the quantitation of the separated components. The potential application of this method for the quantitation of plasma metabolites and antimetabolites such as Ara-C², Ara-U, and F-pyrimidine is describe.     

Extraction and measurement of myocardial nucleotides, nucleosides, and purine bases by high-performance liquid chromatography

Nucleotides, nucleosides, and purine bases were extracted from human endomyocardial biopsies, freeze-clamped rat hearts, and porcine coronary sinus plasma. Perchloric acid extracts were neutralized with Freon-trioctylamine and analyzed at 250 nm by reverse-phase ion-pairing high-performance liquid chromatography. To achieve the sensitivity necessary for analyzing small (1-3 mg wet wt) tissue samples, a small-bore, 2.1-mm-internal-diameter, C18, 5-micron reverse-phase column and a flow rate of 0.2 ml/min were used. All of the myocardial nucleotides and AMP degradation products were resolved in a total separation time of 27 min with 30 mM KH2PO4, 7.5 mM tetrabutylammonium phosphate buffers, and binary pH and acetonitrile gradients.     

Separation of cyclic AMP from adenine and hypoxanthine, their nucleosides and nucleotides by high voltage paper electrophoresis.

A simple and rapid technique which permits the separation of cyclic AMP, adenine, adenosine, hypoxanthine, inosine, 5′-AMP, IMP, ADP, and ATP by the use of unidirectional high-voltage paper electrophoresis has been described. The separation of these compounds based on their charge difference utilizes the following properties: (1) the protonation of the NH₂ group of the adenine, (2) the primary and secondary ionization of the phosphate group of the nucleotides, and (3) the formation of the chelated oxyderivative of boron with the two cis (OH) groups of the ribose moieties of nucleosides and nucleotides.     

Analysis of radioactive and nonradioactive purine bases,nucleosides, and nucleotides by high-speed chromatography on a single column

The concentrations of radioactive and nonradioactive purine bases, purine nucleosides, purine mono-, di-, and trinucleotides in acid extracts of fibroblasts were determined by anion-exchange column chromatography. The concentrations of nonradioactive components were determined by computerized integration of the signal from a double-beam uv-detector. The radioactive metabolites were quantitated by high-efficiency, continuous liquid scintillation counting, employing a discrete sample transport system.     

Adsorption chromatography of cyclic nucleotides on silica gel and alumina thin-layer sheets

Several solvent combinations of graded polarity have been developed, capable of separating cAMP or cGMP, not only from related nucleotides but from bases and nucleosides on alumina and silica gel thin-layer sheets (tls). The solvent system chloroform (C), methanol (M), water (W) (40:20:3) gave effective separations of cAMP on silica gel TLS. Identical results were obtained when this adsorption chromatography method was compared with the ion-exchange chromatography method involving PEI for its effectiveness in the separation of [α-³²P]cAMP formed from [α-³²P]ATP by a preparation of bovine sperm cells. In addition, this solvent system effectively separates cAMP from inosine, hypoxanthine, xanthine, and uric acid which may be useful in determinations of cAMP arising from ³H- or ¹⁴C-prelabeled ATP. Effective separation of cGMP on silica gel tls was accomplished with C:M:W (30:30:5). On alumina tls, cAMP and cGMP were separated from related compounds with M:W combinations; the solvent M:W (50:50) gave the lowest blanks (0.02%) for cGMP and it may prove useful in cGMP determinations.