Mitochondria from L1210 mouse leukemia cells show superstoichiometric → H+/2e- ejection and → Ca2+/2e- uptake ratios in the absence of phosphate. Kinetic analysis of Ca2+-induced respiratory jumps shows a very rapid, early burst of H+ ejection and Ca2+ uptake dependent on energy-coupled electron transport but with extraordinarily high stoichiometry (→H+/2e- > 20; →Ca2+/2e- > 10), followed by a slower phase with normal stoichiometry (→H+/2e-=4-5; →Ca2+/2e-=4.0). The early burst of H+ ejection, which has a higher KM for Ca2+ than respiratory stimulation, accounts for the superstoichiometry phenomenon; it requires energization by state 4 respiration.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Mar 15 1974|
ASJC Scopus subject areas
- Molecular Biology