Effects of ochratoxin a metabolites on yeast phenylalanyl-tRNA synthetase and on the growth and in vivo protein synthesis of hepatoma cells

Creppy, E. E.; Størmer, Fredrik C.; Kern, Daniel; Röschenthaler, R.; Dirheimer, G.

doi:10.1016/0009-2797(83)90160-6

Cited by 57 publications

(29 citation statements)

References 15 publications

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“…The inhibitory constant of this enzyme for OTA (4.33 mM) is more than 150 times higher than its K m for phenylalanine (28/IM) in the aminoacylation reaction. These values are very close to those obtained for yeast PheRS (Ki: 1.3 mM, K,,: 3.3 /IM) [19] but markedly different from those determined by Konrad and R6schenthaler for the Bacillus subtilis enzyme [11]. One reason for this difference may be that pure PheRS and E. coli tRNA Phe were used here.…”

Section: Discussionmentioning

confidence: 49%

Kinetic properties of pure overproduced Bacillus subtilis phenylalanyl‐tRNA synthetase do not favour its in vivo inhibition by ochratoxin A

Roth¹,

Eriani²,

Dirheimer³

et al. 1993

FEBS Letters

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Ochratoxine A (OTA) inhibits growth of Bacillus subtilis at pHs below 7. Since OTA is a phenylalanine analogue, this effect could be due to inhibition of phenylalanine-tRNA synthetase (PheRS) by competition of this mycotoxin with the amino acid. Homogeneous PheRS was purified from Bacillus subtilis and from E. coli transformed with the PheRS gene. The latter produced about 40 times more PheRS than R subtilis. The K m and K, values of PheRS, respectively, for phenylalanine and OTA were measured and their concentrations within the cell determined. It appears that the concentration of OTA in the cell, in spite of a 25-fold accumulation, remained too low to significantly compete with phenylalanine. This does not suggest PheRS to be the target of OTA in cell growth and protein synthesis inhibition in Bacillus subtilis. It was also shown that the 2-3-fold increase of PheRS in OTA-treated cells is not due to phenylalanine-controUed attenuation regulation.

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Section: Discussionmentioning

confidence: 49%

Kinetic properties of pure overproduced Bacillus subtilis phenylalanyl‐tRNA synthetase do not favour its in vivo inhibition by ochratoxin A

Roth¹,

Eriani²,

Dirheimer³

et al. 1993

FEBS Letters

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“…This decrease in the number of Ig-bearing cells may be due to direct inhibitory effects of OTA (transferred in the eggs) on protein synthesis as described by Creppy et al (1983). It is known that a part of the toxicity of OTA is due to a structural homology with the amino acid Values (mean ± SD) in each row (within a given set of progeny) followed by different letters are significantly different (P ≤ 0.05) from one another.…”

Section: Discussionmentioning

confidence: 96%

Immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed

Hassan

Khan

et al. 2011

Journal of Immunotoxicology

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“…69,70) that the mammalien synthetase has a high affinity for ochratoxin A and a low affinity for phenylalanine. Another contributory factor may be that ochratoxin A and its metabolites, some of which are still toxic, accumulate inside cells (ref.…”

Section: Ch2mentioning

confidence: 98%

Biochemical mechanism of action of mycotoxins

Kiessling¹

1986

Pure and Applied Chemistry

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Symptoms of mycotoxicosis are a result of interactions of mycotoxins with functional molecules and subcellular organelles in the animal cell. The biological effects vary mainly according to the diversity in chemical structures of the mycotoxins, but also because of biological, nutritional and environmental factors. For a few mycotoxins, especially aflatoxin B1, so many effects on biochemical systems have been described that only a fraction could be discussed here. Many of these effects are probably secondary to one and the same primary mechanism of action, others occur at such high concentrations that they will never happen in nature. It is striking that so many mycotoxins act on the DNA-RNA level. In most cases this gives rise to consequences on many levels and with pathological pictures caused by many co-operating factors. Less frequently, the effects are as specific as the inhibition of phosphoenolpyruvate carboxykinase by ochratoxin A. Thus no generalized mechanism can apply to all mycotoxins -not even for one and the same mycotoxin in different circumstances. The mechanism of action for a mycotoxin in mammalian cells may not be applicable to plants and microorganisms if metabolic activation is involved. Despite the many data accumulated so far, some of which have been accounted for in this review, the specific lesions responsible for the acute toxicity of many mycotoxins have not yet been identified. Much work therefore remains to be done in order to fully understand their mechanism of action.

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Effects of ochratoxin a metabolites on yeast phenylalanyl-tRNA synthetase and on the growth and in vivo protein synthesis of hepatoma cells

Cited by 57 publications

References 15 publications

Kinetic properties of pure overproduced Bacillus subtilis phenylalanyl‐tRNA synthetase do not favour its in vivo inhibition by ochratoxin A

Kinetic properties of pure overproduced Bacillus subtilis phenylalanyl‐tRNA synthetase do not favour its in vivo inhibition by ochratoxin A

Immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed

Biochemical mechanism of action of mycotoxins

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