Catalysis of the introduction of an omega-6 double bond into the fatty acid hydrocarbon chain.
Synonyms:
xref:
reactome:R-HSA-2046089 "Desaturation of eicosatetraenoyl-CoA to eicosapentaenoyl-CoA"; reactome:R-HSA-2046092 "Desaturation of dihomo-gamma-lenolenoyl-CoA to arachidonoyl-CoA"