Free fatty acids in carrot-tissue preparations and their effect on isolated carrot mitochondria.

Mitochondria isolated from disrupted carrot tissue oxidize succinate more rapidly than all other substrates tested, have relatively high qo2 values, relatively low cofactor requirements and show respiratory control with ADP only when bovine serum albumin (1 %) is present in the homogenization medium. A protective effect of albumin during the isolation or incubation of mitochondria from insect (Lewis & Slater, 1954; Sacktor, O'Neill & Cochran, 1958) and mammalian (Polls & Shmukler, 1957; Weinbach, 1959; Helinski & Cooper, 1960) sources also occurs, and is probably due to its ability to bind free fatty acids (Boyer, Ballou & Luck, 1947; Goodman, 1958). No similar data are available on the mode of action of albumin during the preparation of plant mitochondria. Accordingly the production of free fatty acids during the preparation of carrot mitochondria and the effect of these fatty acids on the function of isolated mitochondria have been investigated. It is concluded that the presence of a variety of fatty acids during the isolation of carrot mitochondria could account for the differences observed in mitochondria prepared with and without added albumin in the homogenization medium.