Swelling of Phaseolus mitochondria in relation to free fatty acid levels.

Freshly isolated Phaseolus vulgaris mitochondria contain, 1.8 micromoles of long chain, primarily unsaturated, free fatty acids per milligram of nitrogen. Although there is no measurable increase in free fatty acid content as a result of spontaneous swelling in buffered KCl, bovine serum albumin strongly inhibits the degree of swelling. The mitochondria only swell slowly in sucrose, but rapid swelling can be induced by the addition of oleic acid in a process inhibited by bovine serum albumin. The possible participation of the endogenous free fatty acids of Phaseolus mitochondria in spontaneous swelling is discussed.