Biology said only proteins could catalyze reactions — then RNA broke the rule

In 1982, Thomas Cech showed that an RNA molecule in Tetrahymena could splice itself with no protein enzyme present. Sidney Altman independently found RNA acting as a catalyst in another system around the same time. The discovery of these 'ribozymes' reshaped theories about how life's chemistry could have started, and both shared the 1989 Nobel Prize in Chemistry.

— Thomas R. Cech et al., Self-Splicing RNA: Autoexcision and Autocyclization of the Ribosomal RNA Intervening Sequence of Tetrahymena — Cell, 1982