Activation of synthesis of hexacosenoic acid by sulfhydryl reagents in swine cerebral microsomes

The elongation of icosenoyl-CoA (20:1-CoA) in swine cerebral microsomes resulted in the synthesis of docosenoic acid (22:1) and tetracosenoic acid (24:1), but the synthesis of hexacosenoic acid (26:1) was negligible. In contrast, in the presence of sulfhydryl reagents (0.6 mM N-ethylmaleimide NEM] or 0.3 mM p-chloromercuriphenylsulfonic acid PCMPS]) the synthesis of 26:1 was remarkably enhanced. We suggest that the synthesis of 26:1 from 20:1-CoA was more enhanced by NEM or PCMPS as a result of activation of the condensation step in the elongation of 24:1 (intermediate) to 26:1.