Effect of bovine serum albumin on membrane potential in plant mitochondria

Abstract

The membrane potential in highly coupled potato (Solanum tuberosum L.) mitochondria, as measured by changes in safranine absorbance, was significantly increased by addition of bovine serum albumin. Purification of potato mitochondria on Percoll, in removing 50% of free unsaturated fatty acids, decreased the BSA‐de‐pendent membrane potential. The effect of added linoleic acid and of the natural accumulation of fatty acids during aging was studied. The response of membrane potential to addition of bovine serum albumin appeared to be directly correlated to the amount of free unsaturated fatty acids. Aging in vitro, in releasing free fatty acids, decreased respiratory control and ADP:O ratios and collapsed the membrane potential. During 2–3 h of incubation, addition of BSA completely restored membrane potential and oxidative phosphorylation. It is concluded that both in fresh and in aged potato mitochondria the effect of bovine serum albumin on oxidative phosphorylation can be ascribed to an effect on membrane permeability to ions. BSA, in binding free unsaturated fatty acids, restored maximal membrane potential. The bovine serum albumin‐dependent membrane potential appears to be a sensitive criterion of the functional integrity of the inner mitochondrial membrane.

Binding of concanavalin A to the outer membrane of potato tuber mitochondria detected by flow cytometry

“…Mitochondria, prepared as in [19], were layered on Percoll step gradients containing 0.3 M mannitol, 0.1% BSA (fraction V, Sigma) and 10 mM Mops (pH 7.2). Each gradient comprised 2 ml of 80% (v/v), 4 ml of 40%, 3 ml of 23% and 3 ml of 10% Percoll mixture in a 15 ml tube.…”

A Specific Ascorbate Free Radical Reductase Isozyme Participates in the Regeneration of Ascorbate for Scavenging Toxic Oxygen Species in Potato Tuber Mitochondria

“…The isolation and purification procedures described below were derived from the method of Diolez and Moreau (1983). Potato tuber batches of 2 kg were chopped into small pieces and repeatedly washed with distilled water.…”

The excellence of turnip mitochondrial fractions

“…Fig. 3 shows that addition of 0.1% BSA (Sigma, fraction V) to the reaction medium improves the coupling condition of mitochondria, binding fatty acids as products of the putative activity of lipases [8] and also by inhibiting the activity of the uncoupling protein [9].…”