The Solubilizing Effect of Lysolecithin on the Extractability of Various Tissues of Rainbow Trout (Salmo gairdneri)

Abstract

Liver homogenate treated with and without lysolecithin (LL) and centrifuged at 1600 g and the supernatant portion centrifuged again at 20,000 g showed disintegration of organelles with disruption of their membranes in the pellet fractions of that which was treated with LL, whereas the organelles of the others were normal. This was seen from the electron micrographs of the pellet fractions. The amino acid composition of the protein fraction of the white skeletal muscle soluble in 0.9% NaCl and of the larger fraction extractable in 0.9% NaCl with LL added were similar. The total nitrogen found in the supernatant fraction of brain, kidney, and liver homogenates reached approximately 44, 59, and 63% in 0.9% NaCl and ≈ 88, 95, and 89% in 0.9% NaCl containing 4 mg/ml LL; whereas the total N present in heart muscle and white muscle homogenates reached approximately 39 and 31% in 0.9% NaCl and ≈ 61 and 51% in 0.9% NaCl containing 4 mg/ml LL. LL destroyed the ability of liver tissue and liver mitochondria to oxidize 14C palmitate. It was concluded that the effect of LL in increasing the amount of protein extractable from fish tissue homogenates arises from its ability to lower surface tension and disrupt membranes and not by affecting protein solubility.