ISSN:
1573-6881
Keywords:
Permeability transition
;
ADP/ATP translocase
;
kinetics
;
adenosine diphosphate
;
carboxya tractyloside
;
bongkekic acid
;
mitochondria
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Low levels of ADP binding at the ADP/ATP translocase caused inhibition of the Ca2+-inducedpermeability transition of the mitochondrial inner membrane, when measured using the shrinkage assay on mitochondria, which have already undergone a transition. Inhibition was preventedby carboxyatractyloside, but potentiated by bongkrekic acid, which increased the affinity forinhibition by ADP. This suggests that inhibition was related to the conformation of thetranslocase. Ca2+ addition was calculated to remove most of the free ADP. Ca2+ added after ADPinduced a slow decay of the inhibition, which probably reflected the dissociation of ADP fromthe translocator. We conclude that the probability of forming a permeability transition pore(PTP) is much greater when the translocase is in the CAT conformation than in the BKAconformation, and, in the absence of CAT and BKA, the translocator is shifted between theBKA and CAT conformations by ADP binding and removal, even in deenergized mitochondria with no nucleotide gradients.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005568630151
