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R J Suhadolnik

Publications and source records attributed to R J Suhadolnik.

At least 91 records · Page 5Linked to original sources
PubMed1978

Stimulation and inhibition of the protein synthetic process by NAD+ in lysed rabbit reticulocytes.

NAD+ at 0.16 mM stimulates the initiation step of the protein synthetic process in lysed rabbit reticulocytes. This conclusion is based on the stimulation of (i) the transfer of formylmethionine from f[35S]Met-tRNAfMet into polypeptide, (ii) the accumulation of the initial dipeptide, methionylvaline, in the presence of pactamycin, and (iii) the formation of the 40 S initiation complex. The effect of NAD+ changes from a stimulatory role on protein synthesis to an inhibitory role at concentrations greater than 0.16 mM. At 4.0 mM NAD+, protein synthesis is inhibited. This has been demonstrated experimentally by using the same three assays described above. In addition, 4.0 mM NAD+ inhibits MettRNAfMet.initiation factor.GTP ternary complex formation. The elongation and termination steps of polypeptide synthesis are not affected by 0.16 to 4.0 mM NAD+. The data presented clearly show that the stimulatory activity of 0.16 mM NAD+ and the inhibitory activity of 4.0 mM NAD+ affects the initiation step of the protein synthetic process in lysed rabbit reticulocytes.

Animals↗
PubMed1976

Separation of nucleic acid hydrolysis products, purines, pyrimidines, nucleosides, nucleotides, ribonucleic acid hydrolyzates, and mixtures from nucleotide syntheses by column chromatography on amberlite XAD-4.

Amberlite XAD-4 resin has been studied as a support for liquid-solid column chromatography. By coating the resin with triethylammonium bicarbonate, a new and unique separation of nucleic acid components has been achieved. Separations are accomplished with a linear gradient of this buffer from 0.1 to 0.4 M. Separation occurs in the following order: inorganic phosphate, purine or pyrimidine bases, 5'-monophosphates, nucleosides and 5'-diphosphates or 5'-triphosphates; the 2'(3')-monophosphates are eluted after either the 5'mono-, di-or triphosphates. The bases and nucleosides are separated in the order: cytosine, uracil, guanine and adenine. Inorganic phosphate and the nucleotides are eluted in the order: inorganic phosphate 5'-mono, di- and tri-phosphates. Excellent separation of the 5'-monophosphates and the 2'(3')-monophosphates is now possible. In each series of 5'-mono-, di- and tri-phosphates or 2'(3')-monophosphates, the elution order is generally cytidine, uridine, guanosine and adenosine. By use of water instead of coating the resin with triethylammonium bicarbonate, the nucleotides and inorganic phosphate are found in the void volume; adenine is eluted very slowly, whereas adenosine is not eluted. Adenosine is eluted only with ethanol-water (1:3). The method is advantageous in that the recovery is quantitative, the buffer is easily removed, the capacity of the column is large (35 mugmoles pergram of resin), flow-rates are high, the time required is short and separations of combinations of inorganic phosphate, bases, nucleosides and nucleotides are now possible that previously could not be accomplished.

Buffers↗
PubMed1976

Biosynthesis of 3'-deoxyadenosine by Cordyceps militaris. Mechanism of reduction.

The biosynthesis of 3'-deoxyadenosine (cordycepin) by Cordyceps militaris has been investigated using [U-14C]adenosine and [3-3H]ribose. Crystallization of the resulting radioactive 3'-deoxyadenosine to a constant specific activity showed incorporation of both labeled compounds. A control showed that the 3H:14C ratio of the AMP isolated from the RNA was the same as the 3H:14C ratio in the 3'-deoxyadenosine. The 14C ratio in the adenine: ribose of the [U-14C]adenosine added to the 3'-deoxyadenosine producing cultures of C. militaris and of the isolated 3'-deoxyadenosine was the same, e.g. 50:50. These data provide strong evidence that adenosine in converted to 3'-deoxyadenosine without hydrolysis of the N-riboside bond. Degradation of the 3-deoxyribose from 3'-deoxyadenosine showed that the 3H was retained on carbon-3. These results suggest that the formation of 3'-deoxyadenosine may proceed by a reductive mechanism similar to that for the formation of 2'-deoxynucleotides.

Adenosine↗