Catalyzes the transfer of sulfur ion from thiosulfate to cyanide, although other thiol compounds, besides cyanide, can act as sulfur ion acceptors (By similarity). It also has weak mercaptopyruvate sulfurtransferase (MST) activity (By similarity). Has a pivotal role in cyanide detoxification (PubMed:40033006). Together with MRPL18, acts as a mitochondrial import factor for the cytosolic 5S rRNA. Only the nascent unfolded cytoplasmic form is able to bind to the 5S rRNA (PubMed:20663881, PubMed:21685364). {ECO:0000250|UniProtKB:P00586, ECO:0000250|UniProtKB:P24329, ECO:0000269|PubMed:20663881, ECO:0000269|PubMed:21685364, ECO:0000269|PubMed:40033006}. This is the function of ENSG00000128311 (TST, thiosulfate sulfurtransferase).