(9Z,12Z,15Z,18Z)-tetracosatetraenoyl-CoA + malonyl-CoA + H(+) => 3-oxo-(11Z,14Z,17Z,20Z)-hexacosatetraenoyl-CoA + CO2 + CoA
(9z,12z,15z,18z)-tetracosatetraenoyl-coa + malonyl-coa + h(+) => 3-oxo-(11z,14z,17z,20z)-hexacosatetraenoyl-coa + co2 + coa
(9Z,12Z,15Z,18Z)-tetracosatetraenoyl-CoA + malonyl-CoA + H(+) => 3-oxo-(11Z,14Z,17Z,20Z)-hexacosatetraenoyl-CoA + CO2 + CoA
(9z,12z,15z,18z)-tetracosatetraenoyl-coa + malonyl-coa + h(+) => 3-oxo-(11z,14z,17z,20z)-hexacosatetraenoyl-coa + co2 + coa