guanosine(26) in tRNA + 2 S-adenosyl-L-methionine <=> N(2)-dimethylguanosine(26) in tRNA + 2 S-adenosyl-L-homocysteine + 2 H(+)
guanosine(26) in trna + 2 s-adenosyl-l-methionine <=> n(2)-dimethylguanosine(26) in trna + 2 s-adenosyl-l-homocysteine + 2 h(+)