Catalysis of the reaction: an (8Z,11Z,14Z)-icosatrienoyl-containing glycerolipid + 2 Fe(II)- + 2 H+ + O2 = (5Z,8Z,11Z,14Z)-eicosatetraenoyl-containing glycerolipid + 2 Fe(III)- + 2 H2O. Also converts an (8Z,11Z,14Z,17Z)-eicosatetraenoyl-containing glycerolipid into a (5Z,8Z,11Z,14Z,17Z)-eicosapentaenoyl-containing glycerolipid.
di-homo-gamma-linolenate delta5 desaturase activity