guanosine(34) in tRNA + queuine <=> queuosine(34) in tRNA + guanine
guanosine(34) in trna + queuine <=> queuosine(34) in trna + guanine
guanosine(34) in tRNA + queuine <=> queuosine(34) in tRNA + guanine
guanosine(34) in trna + queuine <=> queuosine(34) in trna + guanine