Protein patterns of developing mitochondria at the onset of germination in maize (<i>Zea mays</i> L.)

Ivanov, Vladimir N.; Хавкин, Э. Е.

doi:10.1016/0014-5793(76)80152-4

Cited by 6 publications

(1 citation statement)

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“…In the early stages of seed hydration, the mitochondria are functionally deficient and the adenylate energy of the cell is quite low (Ivanov and Khavkin, 1976;Bewley and Black, 1985). Contrary to ATP, the cellular PP i content was found to be five-fold higher in non-dormant than in dormant oat seeds and this level persisted during the hydration (Larondelle et al, 1987).…”

Section: Discussionmentioning

confidence: 99%

ATP synthesis catalyzed by a V-ATPase: an alternative pathway for energy conservation operating in plant vacuoles?

Façanha

Okorokova‐Façanha

2008

Physiol Mol Biol Plants

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The electrochemical H + gradient generated in tonoplast vesicles isolated from maize seeds was found to be able to drive the reversal of the catalytic cycle of both vacuolar H + -pumps (Façanha and de Meis, 1998). Here we describe the reversibility of the vacuolar V-type H + -ATPase (V-ATPase) even in the absence of the H + gradient in a water-Me 2 SO co-solvent mixture, resulting in net synthesis of [γ-32 P]ATP from [ 32 P]P i and ADP. The water-Me 2 SO (5 to 20 %) media promoted inhibition of both PP i hydrolysis and synthesis reactions whereas it slightly affected the ATP hydrolysis and clearly stimulated the ATP synthesis, which was unaffected by uncoupling agents (FCCP, Triton X-100 or NH 4 + ). This effect of Me 2 SO on the ATP⇔ 32 P exchange reaction seems to be related to a decrease of the apparent K m of the V-ATPase for P i . The results are in accordance to the concept that the energetics of ATP synthesis catalysis depends on the solvation energies interacting in the enzyme microenvironment. A possible physiological significance of this phenomenon for the metabolism of desiccation-tolerant plant cells is discussed.

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Section: Discussionmentioning

confidence: 99%