Where are Polyribosomes found?
Polyribosomes or polysome as name suggests, where two or more ribosomes translate mRNA into polypeptides. It helps to increase protein synthesis rate.
Polyribosomes are found prokaryotes and eukaryotes both either free in the cytoplasm or can attach to the endoplasmic reticulum (ER) and the nucleus membranes. They are attached to rough endoplasmic reticulum surface and the outer membrane of the nucleus in eukaryotes. As prokaryotes lack nuclear membrane and membrane bound organelles, thus polyribosomes are found free in cytoplasm in prokaryotes.
Three forms of polyribosomes are:
– Free form
– Cytoskeletal bound
– Membrane bound.
These are differ by poly(A) and non-poly(A) protein binding sequence.