The paper deals with the synthesis of thymine and its derivatives carrying the label at C(6) in the pyrimidine in the methyl group and in deoxy-d-ribose. The molar activity of the preparations ranges from 0.85 to 4.94 PBq/mol. A procedure is proposed for obtaining tritium-labelled thymine compounds: nucleoside, nucleoside mono-, di- and triphosphates.
Authors:M. Frank-Kamenetskaya, G. Knizhnikova, and N. Myasoyedov
The paper describes an enzymic method for obtaining labelled components of nucleic acids—nucleosides and nucleotides—in reactions catalyzed by a polyenzymic preparation from E. coli B. The method enables highly labelled nucleotides to be obtained through the use of precursors carrying the label at positions unaffected in biosynthesis.
Authors:V. Shevchenko, I. Nagayev, and N. Myasoyedov
This is a comparative study of different chromatographic techniques [gas-liquid (GLC), thin-layer (TLC), liquid (LC), high-pressure liquid (HPLC) chromatography] as applied to the analysis and preparative purification of tritium-labelled eicosanoids with a molar radioactivity of 1.8–8.8 TBq/mmol obtained by selective hydrogenation and by chemical or enzymic methods. We demonstrate the possibility of analyzing reaction mixtures and isolating individual multiply labelled eicosanoids with a chemical and radiochemical purity of 95–98%. Special features of HPLC for high molar radioactivity eicosanoids are considered.
Authors:Yu. Zolotarev, D. Zaitzev, V. Penkina, I. Dostavalov, and N. Myasoyedov
Racemic tritium-labelled amino acids were separated into optical isomers by chromatography on a chiral polyacrylamide sorbent filled with copper ions. The polyacrylamide sorbent is synthesized by Mannich's reaction through the action of formaldehyde and L-phenylalanine upon polyacrylamide Biogel P-4 in an alkali phosphate buffer. Tritiumlabelled amino acids are eluted by a weak alkali solution of ammonium carbonate. Data are presented on the ligand exchange chromatography of amino acids depending on the degree to which the sorbent is filled with copper ions and on the eluent concentration. Conditions are suggested for the quantitative separation of amino acid racemates. Amino acids are isolated from the eluent on short columns filled with sulfonated cation exchanger in the H+ form. HPLC on modified silica gel sorbents is also used for the analysis of tritium-labelled optically active amino acids. Amino acids are eluted by a weakly acidic water-methanol solution containing ammonium acetate. UV and scintillation flow type detectors are used.