Activation of fatty acids by non-glyoxysomal peroxisomes

Abstract

Peroxisomes from mung-bean hypocotyls catalyze, in the presence of fatty acids, CoASH, ATP, and MgCl₂, the formation of acyl-CoA, AMP, and pyrophosphate in a 1:1:1 stoichiometry. This observation demonstrates that the peroxisomes of mung-bean hypocotyls possess an acyl-CoA synthetase (EC 6.2.1.3) for fatty-acid activation. Acyl-CoA synthetase activity is associated with the non-glyoxysomal peroxisomes from various tissues. The acyl-CoA synthetase of the peroxisomes of the mung-bean hypocotyl utilizes oleic, linoleic, and linolenic acid most effectively (3 nkat·mg^-1 peroxisomal protein). In contrast to the β-oxidation enzymes of the peroxisomes whith are largely solubilized in the presence of 0.2 mol·l^-1 KCl, the acyl-CoA synthetase remains associated with the membrane fraction of peroxisomes. On the basis of the latency of the enzyme and its resistance to protease treatment of the peroxisomes, it is concluded that the enzyme is located at the matrix face of the peroxisome membrane.