Inorganic pyrophosphatase of rat liver mitochondria. Correlation of latency with catalytic properties and intramitochondrial location.

Stimulation of Mg(2+)-dependent inorganic pyrophosphatase activity several fold by disruption of mitochondrial membranes does not appreciably alter the catalytic properties of the enzyme. Stimulation is due to increased accessibility of substrate to the enzyme, which is not solublized on activation. The enzyme is attached to the inside of the inner membrane, and under physiological conditions probably hydrolyzes only intramitochondrially-produced PP(i).