Mitochondrial ribosome recycling factor, also known as MRRF, is a 262 amino acid protein that belongs to the ribosome recycling factor (RRF) family. Localized to mitochondria, MRRF is responsible for the release of ribosomes from messenger RNA at the termination of protein biosynthesis. It may increase the efficiency of translation by recycling ribosomes from one round of translation to another. MRRF belongs to the RRF family. 8 isoforms of the human protein are produced by alternative splicing.