Essential peptidyl-tRNA hydrolase component of the mitochondrial large ribosomal subunit (PubMed:20186120, PubMed:33878294). Acts as a codon-independent translation release factor that has lost all stop codon specificity and directs the termination of translation in mitochondrion, possibly in case of abortive elongation (PubMed:33878294). Involved in the hydrolysis of peptidyl-tRNAs that have been prematurely terminated and thus in the recycling of stalled mitochondrial ribosomes (PubMed:20186120, PubMed:33878294). {ECO:0000269|PubMed:20186120, ECO:0000269|PubMed:33878294}. This is the function of MRPL58 (mitochondrial ribosomal protein L58, Ensembl gene identifier ENSG00000167862).