Influence of nh on the oxygen uptake of mitochondria isolated from corn and pea shoots

Tomoyuki Yamaya, Hideaki Matsumoto

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Mitochondria isolated by PercoU density gradient centrifugation from both corn and pea shoots contain approximately 4 nmol NH,+ per mg of mitochondrial protein. Higher concentrations of NH,+. up to 45 mM. had no effect on the rate of mitochondrial oxygen uptake when malate was used as the respiratory substrate. Oxidation of succinate. citrate, or glycine by either types of mitochondria was also resistant to 20 mM of NH,+. The rate of a-ketoglutarate oxidation at state 3 was reduced a little. Thus. oxidative phosphorylation of corn and pea mitochondria was found to be resistant to relatively high concentrations of NH,+. Corn mitochondria were also able to oxidize glutamate and its oxidation at state 3 was stimulated slightly by NH,+. On the other hand, NH,+ reduced the glutamate oxidation by pea mitochondria. Aminooxyacetate (1 mM) strongly inhibited the glutamate oxidation by mitochondria. This result indicates that the major route of glutamate oxidation proceeds via a transamination reaction rather than a direct deamination by glutamate dehydrogenase.

Original languageEnglish
Pages (from-to)513-520
Number of pages8
JournalSoil Science and Plant Nutrition
Volume31
Issue number4
DOIs
Publication statusPublished - 1985 Dec

Keywords

  • Glutamate dehydrogenase
  • NH+ tolerance (mitochondria)
  • Photorspiratory nitrogen cycle
  • Plant mitochondria

ASJC Scopus subject areas

  • Soil Science
  • Plant Science

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