The largest ribonucleoprotein component of RIBOSOMES. It contains the domains which catalyze formation of the peptide bond and translocation of the ribosome along the MESSENGER RNA during GENETIC TRANSLATION.

Synonyms: Ribosomal Subunits, Large Large Ribosomal Subunits Subunits, Large Ribosomal Subunit, Large Ribosomal Large Ribosome Subunit Ribosome Subunit, Large Large Ribosomal Subunit Subunits, Large Ribosome Large Ribosome Subunits Subunit, Large Ribosome Ribosome Subunits, Large Ribosomal Subunit, Large