Evidence for the absence of the terminal adenine nucleotide at the amino acid-acceptor end of transfer ribonucleic acid in non-lactating bovine mammary gland and its inhibitory effect on the aminoacylation of rat liver transfer ribonucleic acid

Herrington, M. D.; Hawtrey, A. O.

doi:10.1042/bj1160405

Cited by 20 publications

(7 citation statements)

References 28 publications

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“…There are of course other factors than the balanced amino acid mixture, tRNAs, tRNA synthesis and aminoacyl transferases which may limit cell-free 14C-amino acid incorpo ration. A deficiency in active nucleotide incorporating enzyme catalyzing the incorporation of cytosine and adenine in deacylated tRNA [83], in initiation factors [84] or in the relative proportion of the different species of charged isoaccepting tRNA [85] within the placental pH 5 preparation may play a role in this. In any case, our cell-free approach to evaluate the capacity for specific placental peptide synthesis [42] should provide a viable alternative to the use of placental slice incubation systems.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Studies of Human Placenta II.

Em¹,

Sg²,

Hn³

1973

Neonatology

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In 18 term placentas obtained from normal pregnancies in a US urban middle class population, the DNA content averaged 1,346 mg, RNA content 1,637 mg and protein content 58.3 g. C Comparisons were made with similar determinations on placentas obtained at 10–18 weeks of pregnancy and on hydatidiform mole and choriocarcinoma tissue. Only in choriocarcinoma were DNA, RNA, and protein content per gram wet tissue higher than in either early or term placenta or in hydatidiform mole. Polysomes were obtained from these 18 placentas and their capacity to program cell-free peptide synthesis compared with that observed with polysomes from early placentas, hydatidiform mole and choriocarcinoma. In all cases, cell-free peptide synthesis was highly dependent on the state of stabilization of the polysomes and on the origin of the pH 5 protein preparation used as a source of transferring and activating enzymes. Among inhibitors of ribonuclease, only 0.5–2.0 mM EDTA stabilized the free and membrane-bound polysomes from early and term placentas. Similarly, only 3–5% bentonite stabilized polysomes from choriocarcinoma. The polysomes from hydatidiform mole showed a different pattern: their membrane-bound polysomes remained aggregated in the absence of exogenous ribonuclease inhibitors whereas their free polysomes were uniquely stabilized by 2–3% bentonite. Under optimal conditions for isolation, the polysome-monosome ratio was 3 to 1 in both normal and tumor trophoblast. Membrane-bound ribosomes accounted for 9–35% of the total ribosome complement in these preparations with the balance being free ribosomes. Rat liver pH 5 enzyme was significantly more effective in cell-free peptide synthesis than the autologous early or late placental pH 5 enzyme. When activated by rat liver pH 5 enzyme, there was a similar magnitude of ¹⁴C-peptide synthesis in cell-free systems programmed by properly stabilized polysomes obtained from early or term placentas or from tumor trophoblast.

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Section: Discussionmentioning

confidence: 99%

Quantitative Studies of Human Placenta II.

Em¹,

Sg²,

Hn³

1973

Neonatology

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“…Bovine tRNA. In a previous paper (Herrington & Hawtrey, 1970) it was shown that tRNA isolated from non-lactating bovine mammary gland by phenol-sodium dodecyl sulphate extraction is unable to accept amino acids due to the absence of the terminal trinucleotide sequence. The results presented in Table 3, however, illustrate that tRNA isolated from lactating bovine mammary gland is quite capable of accepting amino acids to a degree more efficient than that of deacylated rat liver Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…Attempts to demonstrate the incorporation of amino acids into protein by subcellular fractions derived from non-lactating bovine mammary gland have met with little success (Herrington & Hawtrey, 1969a). This failure has been attributed to the presence of active nucleases in the cytoplasm and to tRNA, which appears to be unable to accept amino acids due to the absence of the terminal trinucleotide sequence -pCpCpA (Herrington & Hawtrey, 1970).…”

Section: Discussionmentioning

confidence: 99%

“…Studies on non-lactating bovine mammarygland tRNA have indicated that the molecule when isolated in the absence of ribonuclease inhibitors is unable to accept amino acids due to the lack of the terminal adenine nucleotide and possibly the terminal -pCpCpA nucleotide sequence (Herrington & Hawtrey, 1970). Once these nucleotides have been replaced by utilizing the rat liver nucleotideincorporating enzyme in the presence of ATP and CTP, the molecule is able to both accept amino acids and transfer these amino acids to the growing polypeptide chain present on the ribosomes.…”

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confidence: 99%

“…(4) Aminoacyl-tRNA synthetases. These were prepared from the rat liver pH5 enzyme according to the method of Hele (1961) as modified by Herrington & Hawtrey (1970).…”

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confidence: 99%

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Competing addition and hydrolysis of the cytidylylcytidylyladenosine terminal residues of transfer ribonucleic acid isolated from the non-lactating bovine mammary gland

Herrington

Hawtrey

1970

Biochemical Journal

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1. The enzyme fraction obtained from the pH5 enzyme of non-lactating bovine mammary gland between 40 and 100% ammonium sulphate saturation markedly inhibited the AMP-incorporating activity of rat liver nucleotide-incorporating enzyme. This inhibitory effect has been attributed to high nuclease activity which can be partially removed by adsorption of the enzyme fraction on to calcium phosphate gel. 2. The degradation action of the calcium phosphate-purified enzyme is confined mainly to the terminal trinucleotide sequence -pCpCpA of tRNA, its effect being analogous to that of venom phosphodiesterase. This enzyme is heat labile and very readily loses its degradative activity. 3. Treatment of the enzyme fraction with Macaloid results in complete removal of the phosphodiesterase, leaving an enzyme capable of incorporating AMP into tRNA. 4. Transfer RNA extracted from non-lactating bovine mammary gland in the presence of polyvinyl sulphate and Macaloid is able to accept amino acids with an efficiency 30% of that shown by lactating bovine mammary-gland tRNA isolated under identical conditions.

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Functional changes in rat liver tRNA following aflatoxin B1 administration

Bhattacharya

Aboobaker

1981

J Biosci

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Evidence for the absence of the terminal adenine nucleotide at the amino acid-acceptor end of transfer ribonucleic acid in non-lactating bovine mammary gland and its inhibitory effect on the aminoacylation of rat liver transfer ribonucleic acid

Cited by 20 publications

References 28 publications

Quantitative Studies of Human Placenta II.

Quantitative Studies of Human Placenta II.

Competing addition and hydrolysis of the cytidylylcytidylyladenosine terminal residues of transfer ribonucleic acid isolated from the non-lactating bovine mammary gland

Functional changes in rat liver tRNA following aflatoxin B1 administration

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