(5Z,11Z,14Z)-eicosatrienoyl-CoA + 2 Fe(III)-[cytochrome b5] + 2 H2O => (11Z,14Z)-eicosadienoyl-CoA + 2 Fe(II)-[cytochrome b5] + O2 + 2 H(+)
(5z,11z,14z)-eicosatrienoyl-coa + 2 fe(iii)-[cytochrome b5] + 2 h2o => (11z,14z)-eicosadienoyl-coa + 2 fe(ii)-[cytochrome b5] + o2 + 2 h(+)