Zinc phosphodiesterase, which displays mitochondrial tRNA 3'- processing endonuclease activity. Involved in tRNA maturation, by removing a 3'-trailer from precursor tRNA (PubMed:21593607). Associates with mitochondrial DNA complexes at the nucleoids to initiate RNA processing and ribosome assembly (PubMed:24703694). . This is the function of ELAC2 (elaC ribonuclease Z 2, ENSG00000006744).