SOLUBILIZATION OF ACYL-COA ELONGASES FROM DEVELOPING RAPESEED (BRASSICA-NAPUS L)

Acyl-CoA elongases are important in producing high-erucic acid rapeseed. The effects of Triton X-100, N-octyl-beta-D-glucopyranoside and deoxycholate on the C18:1-CoA and C20:1-CoA elongase(s) have been studied by using a 15,000 X g pellet from developing rapeseed. The synthesis of very long chain monounsaturated fatty acids (VLCMFA) and, in particular, that of erucic acid were stimulated by Triton X-100, whatever the substrate used. In the presence of N-octyl-beta-D-glucopyranoside, the elongase activity was practically unchanged, whereas deoxycholate strongly inhibited VLCMFA synthesis. Triton X-100 was chosen for the solubilization, at an optimal Triton X-100/protein (w/w) ratio of 2.5. Acyl-CoAs were the major products synthesized by the solubilized acyl-CoA elongase(s). The analysis of the reaction intermediates showed that the entire elongation complex has been solubilized and was still functional.