When complexed with ribosomes GFM2 (EF-G2mt) hydrolyzes GTP and, together with MRRF, acts as a ribosome releasing factor by splitting 55S ribosomes into 28S and 39S subunits (Tsuboi et al. 2009). Though GTP is hydrolyzed during the reaction, hydrolysis is not necessary for splitting the 55S ribosome into 39S and 28S subunits, but is necessary for dissociation of GFM2 (as GFM2:GDP) and MRRF from the large ribosomal subunit after splitting (Tsuboi et al. 2009).
GTPase activity of 55S ribosome:MRRF:GFM2:GTP [mitochondrial inner membrane]