Abstract
The decrease in pyridine nucleotide coenzymes which occurs during poisoning of Escherichia coli by hyperbaric oxygen or paraquat is not due to impairment of nicotinatemononucleotide pyrophosphorylase (carboxylating) [EC 2.4.2.19] as was previously proposed (Brown, O.R. et al. Biochem. Biophys. Res. Commun. 91:982-990; 1979). This was shown directly using extracts of E. coli, prepared after exposure to 1 mM paraquat or 4.2 atmospheres of oxygen. The enzyme also was not impaired in Neurospora crassa by 1 mM paraquat. A naturally-occurring, non-dialyzable inhibitor of the enzyme was found in E. coli extracts. The inhibitor caused the erroneous, low nicotinatemononucleotide pyrophosphorylase (carboxylating) activities previously reported in extracts of E. coli poisoned by paraquat.
Original language | English (US) |
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Pages (from-to) | 113-116 |
Number of pages | 4 |
Journal | Free Radical Biology and Medicine |
Volume | 8 |
Issue number | 2 |
DOIs | |
State | Published - 1990 |
Externally published | Yes |
Keywords
- Free radicals
- Nicotinatemononucleotide pyrophosphorylase (carboxylating)
- Oxidant stress
- Oxygen toxicity
- Paraquat toxicity
- Pyridine nucleotide coenzymes
- Superoxide
ASJC Scopus subject areas
- Biochemistry
- Physiology (medical)