Studies on the mechanism of mitochondrial protection by polymeric prostaglandin PGBx.

On the basis of the interaction between tritiated PGBx and rat liver mitochondria, it appears that PGBx interacts with rat liver mitochondria to form a complex. At low PGBx-mitochondrial ratios, one effect of this complex formation is to stabilize the phosphorylation activity of rat liver mitochondria when exposed for short times to hypotonic solutions. At higher PGBx-mitochondrial ratios, PGBx fails to show this effect.

Mechanism of polymeric prostaglandin PGBx for in vitro stabilization of rat liver mitochondrial oxidative phosphorylation.

The mechanism of the in vitro PGBx effect on mitochondria was studied by determining the specific requirements of the assay system composition. These studies showed that (a) rat liver mitochondria must first be exposed to hypotonic media containing PGBx under aerobic conditions, (b) oxygen, Pi, Mg++, phosphate acceptor (nucleotides), and some oxidizable substrates are essential components to yield optimal phosphorylation values. KCl and bovine serum albumin are non-essential components.

Interaction of bovine serum albumin with PGBx (polymeric 15-keto-prostaglandin B1).

Bovine serum albumin (BSA) interacts with PGBx, a polymeric derivative of 15-keto-prostaglandin B1, to form a complex that does not exhibit the fluorescence of free BSA. The complex is soluble at pH 5.2 in contrast to free PGBx, which is insoluble.