Ribosomes have following enzymatic activity

Evidence That rRNA Is a Peptidyl Transferase * Ribosomes can make peptide bonds (albeit inefficiently) even when proteins are removed or inactivated. * Ceain pas of the rRNA sequence are highly conserved in all species. * These conserved regions are on the surface of the RNA molecule. * RNA can be catalytic in many other chemical reactions. * Mutations that result in antibiotic resistance at the level of protein synthesis are more often found in rRNA than in the protein components of the ribosome.Ref: Harpers Illustrated Biochemistry, 30th edition, page no: 423, table 37-3