The natural substrate for this enzyme may be peptidyl-tRNAs which drop off the ribosome during protein synthesis. an N-acyl-L-alpha-aminoacyl-tRNA + H2O = a tRNA + an N-acyl-L-amino acid + H(+) Monomer. Ubiquitinated by PRKN during mitophagy, leading to its degradation and enhancement of mitophagy. Deubiquitinated by USP30. Belongs to the PTH2 family.