20-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoate + reduced [NADPH--hemoprotein reductase] + O2 = 20-oxo-(5Z,8Z,11Z,14Z)-eicosatetraenoate + oxidized [NADPH--hemoprotein reductase] + 2 H2O + H(+) — reaction