(5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA + malonyl-CoA + H(+) => (7Z,10Z,13Z,16Z)-3-oxodocosatetraenoyl-CoA + CO2 + CoA
(5z,8z,11z,14z)-eicosatetraenoyl-coa + malonyl-coa + h(+) => (7z,10z,13z,16z)-3-oxodocosatetraenoyl-coa + co2 + coa