THE BIOSYNTHESIS OF AMINO ACID ACCEPTOR RNA

1964 ◽  
Vol 42 (6) ◽  
pp. 859-870 ◽  
Author(s):  
R. A. Cook ◽  
J. P. Bouchard ◽  
M. J. Fraser
Keyword(s):  
Amino Acid ◽  
Tumor Cells ◽  
Actinomycin D ◽  
Ehrlich Ascites Carcinoma ◽  
Ehrlich Ascites ◽  
Specific Activities ◽  
Dna Template ◽  
Acceptor Capacity ◽  
Amino Acid Acceptor

Preliminary observations have been made on the biosynthesis of amino acid acceptor RNA in the mouse Ehrlich ascites carcinoma. Measurements have been made of the incorporation of radioactivity from either14C-CH3-methionine or uridine-2-14C into the RNA of nuclear and cytoplasmic fractions which precipitate at pH 5.0 from 105,000 × g supernatants of broken nuclei preparations and of cell homogenates ("soluble" RNA or sRNA). With either labelled precursor higher specific activities were found in the nuclear than in the cytoplasmic sRNA fractions. Whereas actinomycin D and DNase inhibited the incorporation of radioactivity from uridine-2-14C into nuclear sRNA, these agents stimulated significantly the incorporation of radioactivity from14C-CH3-methionine. The glycine acceptor capacity of nuclear sRNA was found to be greater than that of cytoplasmic sRNA. The base ratios of the amino acid acceptor RNA fractions derived from nuclear sRNA and from cytoplasmic sRNA by chromatography on methylated albumin columns were very similar. The results are consistent with the hypothesis that the amino acid acceptor RNA is made on a DNA-template in the nucleus of the tumor cells, is subsequently released from the template, methylated, and then transferred to the cytoplasm.

Some properties of cytoplasmic RNA fractions of the mouse Ehrlich ascites carcinoma

1968 ◽  
Vol 46 (2) ◽  
pp. 155-166 ◽  
Author(s):  
K. Hosokawa ◽  
M. J. Fraser
Keyword(s):  
Amino Acid ◽  
Ribosomal Rna ◽  
Gradient Centrifugation ◽  
Heterogeneous Material ◽  
Ehrlich Ascites Carcinoma ◽  
Molar Ratio ◽  
5S Rna ◽  
Sucrose Density Gradient Centrifugation ◽  
Ehrlich Ascites ◽  
Amino Acid Acceptor

Two RNA subfractions from mouse Ehrlich ascites carcinoma 105 000 × g supernatant and three RNA subfractions from the tumor microsomal fraction have been resolved by chromatography on methylated albumin–kieselguhr. The five subfractions have been examined for their amino acid acceptor capacities and nucleotide compositions and by sucrose density-gradient centrifugation. One of the 105 000 × g supernatant fractions has been identified as amino acid acceptor or transfer RNA (tRNA) and the three microsomal components have been identified as tRNA, 5S RNA, and ribosomal RNA. The microsomal tRNA and 5S RNA appear to be associated with ribosomal RNA in a molar ratio approaching 2:1 and together make up about 6–8% of the total microsomal RNA. The second 105 000 × g supernatant RNA fraction has not been identified. It is recovered in widely varying amounts and behaves like heterogeneous material in chromatographic and sedimentation procedures.

COMPETITION BETWEEN AMINO ACIDS FOR TRANSPORT INTO EHRLICH ASCITES CARCINOMA CELLS

1961 ◽  
Vol 39 (11) ◽  
pp. 1717-1735 ◽  
Author(s):  
P. G. Scholefield
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Amino Acid ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Transport Systems ◽  
Radioactive Carbon ◽  
Ehrlich Ascites ◽  
Competitive Inhibitors ◽  
Amino Acid Analogues

The cumulative entry of amino acids into Ehrlich ascites carcinoma cells is due to the presence of active transport systems, each with its own specific range of substrates. Several amino acids and amino acid analogues may have an affinity for the same transport system and thus may inhibit transport of other amino acids by acting as competitive inhibitors or competitive substrates. Loss of methionine from ascites cells takes place by a diffusion process which obeys Fick's law. Leucine accumulation by ascites cells is small and is increased on addition of certain other amino acids. The increase is not due to inhibition of leucine oxidation as increase in the rate of production of radioactive carbon dioxide from labeled leucine also occurs. Kinetic aspects of these results are discussed.

A SENSITIVE METHOD FOR MEASUREMENT OF AMINO ACYL RIBONUCLEIC ACID SYNTHETASE ACTIVITIES

1962 ◽  
Vol 40 (1) ◽  
pp. 653-666 ◽  
Author(s):  
Murray J. Fraser
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Liver ◽  
Ribonucleic Acid ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Ehrlich Ascites ◽  
Sensitive Method

A sensitive method for the measurement of amino acyl RNA synthetase activities (amino acid activating enzymes) is described. The method is based on measurements of the rates of labelling of soluble ribonucleic acid with14C-amino acids. Determinations of α-glutamyl-RNA, glutaminyl-RNA, and glycyl-RNA synthetase activities in the "pH 5 enzymes" fractions from rat liver and mouse Ehrlich ascites carcinoma cells have been made.

THE ENZYMIC FORMATION OF 6-(METHYLMERCAPTO)PURINE RIBONUCLEOSIDE 5′-PHOSPHATE

1966 ◽  
Vol 44 (2) ◽  
pp. 229-245 ◽  
Author(s):  
Ian C. Caldwell ◽  
J. Frank Henderson ◽  
A. R. P. Paterson
Keyword(s):  
Tumor Cells ◽  
Blood Cells ◽  
Intraperitoneal Injection ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Ehrlich Ascites ◽  
Mouse Tissues ◽  
Enzymatic Methods

6-(Methylmercapto)purine ribonucleoside (Me6MPR) is efficiently phosphorylated in mouse tissues and in Ehrlich ascites carcinoma cells in vivo; tumor cells in vitro and cell-free extracts of the tumor also phosphorylate this analogue ribonucleoside. The product of this reaction has been identified by chemical and enzymatic methods and by its chromatographic behaviour as Me6MPR 5′-phosphate. The evidence presented in this report indicates that no other major metabolites of Me6MPR are formed.The phosphorylation of Me6MPR by cell-free tumor extracts requires ATP and Mn2+ (or Mg2+), and evidence is presented that the reaction is probably mediated by adenosine kinase.Me-14C-6MPR is rapidly taken up by most mouse tissues following its intraperitoneal injection. Forty minutes after injection of the labeled drug, the highest levels of radioactivity were found in intestine, liver, blood cells, lung, and spleen, in descending order; virtually no radioactivity was found in brain tissue or in blood plasma.

A SENSITIVE METHOD FOR MEASUREMENT OF AMINO ACYL RIBONUCLEIC ACID SYNTHETASE ACTIVITIES

1962 ◽  
Vol 40 (5) ◽  
pp. 653-666 ◽  
Author(s):  
Murray J. Fraser
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Liver ◽  
Ribonucleic Acid ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Ehrlich Ascites ◽  
Sensitive Method

A sensitive method for the measurement of amino acyl RNA synthetase activities (amino acid activating enzymes) is described. The method is based on measurements of the rates of labelling of soluble ribonucleic acid with14C-amino acids. Determinations of α-glutamyl-RNA, glutaminyl-RNA, and glycyl-RNA synthetase activities in the "pH 5 enzymes" fractions from rat liver and mouse Ehrlich ascites carcinoma cells have been made.

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