Tags: Protein.
28S ribosomal protein S21 mitochondrial is a protein that in humans is encoded by the MRPS21 gene.Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and assist protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes where this ratio is reversed.