Display options
Share it on

Plant Physiol. 1979 Aug;64(2):276-80. doi: 10.1104/pp.64.2.276.

Energy-linked Adenosine Diphosphate Accumulation by Corn Mitochondria: I. General Characteristics and Effect of Inhibitors.

Plant physiology

S Abou-Khalil, J B Hanson

Affiliations

  1. Department of Botany, University of Illinois, Urbana, Illinois 61801.

PMID: 16660948 PMCID: PMC543070 DOI: 10.1104/pp.64.2.276

Abstract

Corn mitochondria show respiration-linked net accumulation of [(3)H]ADP in the presence of phosphate and magnesium, especially if the formation of ATP is blocked with oligomycin. Inhibition of ADP-ATP exchange by carboxyatractyloside also activates ADP accumulation, and addition of carboxyatractyloside or palmitoyl-coenzyme A to oligomycin-blocked mitochondria produces additional ADP uptake. With carboxyatractyloside the accumulated ADP is phosphorylated to ATP. With oligomycin, only a little ATP is formed. Millimolar concentrations of ADP are required for maximum uptake, and the K(m) (3.77 millimolar) for ADP translocation is independent of whether oligomycin or carboxyatractyloside is used. This is not true for ADP concentrations in the 0.05 to 0.25 millimolar range. Accumulated [(3)H]ADP rapidly exchanges with unlabeled AMP, ADP, or ATP, but not with other diphosphate nucleotides or 2 millimolar substrate anions. [(3)H]AMP is not accumulated, but [(3)H]ATP is accumulated to about one-half the extent of [(3)H]ADP. Tricarboxylate substrates inhibit ADP net uptake, and inhibition by citrate is competitive with K(i) = 10 millimolar. The evidence suggests the presence of a pathway, carboxyatractyloside-insensitive and different from the translocase, which operates to maintain adenine nucleotides in the matrix.

References

  1. Biochem Biophys Res Commun. 1978 Jan 13;80(1):193-8 - PubMed
  2. Plant Physiol. 1969 Sep;44(9):1335-41 - PubMed
  3. Biochem J. 1968 Feb;106(3):759-66 - PubMed
  4. Biochim Biophys Acta. 1976 Apr 30;456(1):1-38 - PubMed
  5. J Biol Chem. 1965 May;240:2254-61 - PubMed
  6. Arch Biochem Biophys. 1975 Jun;168(2):358-68 - PubMed
  7. Plant Physiol. 1977 Dec;60(6):933-4 - PubMed
  8. FEBS Lett. 1970 May 11;8(1):41-44 - PubMed
  9. Arch Biochem Biophys. 1977 Oct;183(2):581-7 - PubMed
  10. J Biol Chem. 1971 Jan 25;246(2):402-11 - PubMed
  11. Proc Natl Acad Sci U S A. 1978 Oct;75(10):4788-92 - PubMed
  12. J Biol Chem. 1975 May 25;250(10):3639-43 - PubMed
  13. Plant Physiol. 1974 Sep;54(3):250-6 - PubMed
  14. Biochim Biophys Acta. 1976 Sep 13;440(3):688-96 - PubMed
  15. Arch Biochem Biophys. 1973 Nov;159(1):279-91 - PubMed
  16. Anal Biochem. 1967 Dec;21(3):435-43 - PubMed
  17. Biochem J. 1969 Mar;111(5):665-78 - PubMed
  18. J Biol Chem. 1951 Nov;193(1):265-75 - PubMed

Publication Types