The oxidation of fatty acids by a particulate fraction from desert-locust (Schistocerca gregaria) thorax tissues

Abstract

The isolation of a particle system from locust thorax tissue is described; the tissues were derived from insects kept at 35[degree] and at 45[degree] (35[degree] particles (P) and 45[degree] P). The 35[degree] P oxidized butyrate completely, but were unable to oxidize higher fatty acids; the 45[degree] P oxidized both. The 35[degree] P system required adenosine triphosphate and Mg++; the 45[degree] P system showed, for the oxidation of butyrate and higher fatty acids, the additional requirement for coenzyme A, and required for the oxidation of higher fatty acids a factor present in sheep-liver extracts. Both systems were partially inhibited by azide, cyanide, arsenite, malonate, fluoride, 2,4-dinitrophenol (DNP) and ethylene-diaminetetra-acetic acid (EDTA). The oxidation of higher fatty acids and butyrate in the 45[degree] system was inhibited by higher concentrations of the C8-C18 fatty acids. The minimal inhibiting concentration of each fatty acid decreased with increasing chain length. The 35[degree] system when oxidizing butyrate showed oxidative phosphorylation, which could be abolished by DNP and EDTA. The fatty acid-oxidizing systems found were compared with similar systems of mammalian origin. Reasons are advanced for believing that the differences between the 35[degree] P and the 45[degree] P are due to changes in the properties of the particle surface. The possible physiological significance of the results is discussed.