Catalyzes the formation of 3-(3-amino-3-carboxypropyl)uridine (acp3U) at position 20a in the D-loop of several cytoplasmic tRNAs (acp3U(20a)) . Also has a weak activity to form acp3U at position 20 in the D-loop of tRNAs (acp3U(20)) .
[Isoform 1]: Cytoplasm .; [Isoform 2]: Nucleus . Cytoplasm . Localizes mainly in the nucleus. .