The function of HEMK1 (HemK methyltransferase 1, mitochondrial release factors N(5)-glutamine, ENSG00000114735) is as follows. N5-glutamine methyltransferase responsible for the methylation of the glutamine residue in the universally conserved GGQ motif of the mitochondrial translation release factors MTRF1, MTRF1L, MRPL58/ICT1 and MTRFR. {ECO:0000269|PubMed:18541145, ECO:0000269|PubMed:35260756}.