title: [How did protoproteins originate?].
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis; D000818:Animals; D005075:Biological Evolution; D009842:Oligopeptides / Q000096:biosynthesis; D014176:Protein Biosynthesis; D013768:Tetrahymena
chemical_list: D000596:Amino Acids; D009842:Oligopeptides