Properties of mitochondria isolated from the cotyledons of (Phaseolus vulgaris).

Actively respiring mitochondrial fraction has been Isolated from the cotyledons of Phaseolus
vulgaris. Polarographic studies indicate a respiratory control ratio of 5,0 and ADP/O ratio
of I'Z with succinate as substrate. Michaelis Constant values for ADP, succinate and inorganic
phosphate are 76, 200 and 64 pM respectively. Plant growth regulators like 2,4,5-trichlorophenoxyacetate
and 2.4-dichlorophenoxyacetate inhibit oxidative phosphorylation at a concentration
of IO-4M. These mitochondria undergo swelling in presence of both KCI and carbon tetrachloride.
The swelling induced by KCI is reversed by the addition of succinate but not by the
addition of ATP, whereas the swelling: induced by carbon tetrachloride is reversed by ATP and
not by the addition of succinate. ATP supported calcium uptake in these mitochondria takes
place at lower calcium chloride concentrations.