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Organotin compounds as energy‐potentiated uncouplers of rat liver mitochondria
Author(s) -
Connerton Ian F,
Griffiths David E
Publication year - 1989
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.590030611
Subject(s) - chemistry , atp synthase , halide , oxidative phosphorylation , membrane potential , atpase , mitochondrion , chloride , membrane , atp hydrolysis , biochemistry , biophysics , hydrolysis , enzyme , stereochemistry , inorganic chemistry , organic chemistry , biology
Triorganotins will titrate membrane potential (Δψ) and the accompanying pH gradient (ΔpH) in estimates of protonmotive force (Δ p ) in isolated rat liver mitochondria in an apparent concentrationdependent manner and in minimal halide media (5 μmol dm −3 ). Under these conditions the concentrations of organotin required to produce a drop of 80–120mV in Δ p approach or are in excess of those required to inhibit ATP‐synthase activity, which are at least three‐fold greater than those which inhibit ATP hydrolytic activity. The addition of exogenous chloride ion did not appreciably alter the steady‐state or rate estimates of triorganotin‐mediated membrane potential (Δψ) depolarization. The evidence indicates that triorganotins possess an uncoupling effect which is independent of halide/hydroxyl exchange or direct inhibition of the ATPase complex. The activity of various triorganotins may be best understood according to their abilities to uncouple or directly inhibit oxidative phosphorylation at the enzymic level, in the absence of halide/hydroxyl exchange.